Hitman's Pontiac Trans Am Forum
Trans Am Information => Trans Am Tech => Electrical => Topic started by: jphillips3333 on April 03, 2009, 01:05:04 PM
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Grabbed some new bulbs for the tail light assembly - snapped them in. The blinkers worked - I thought they were faster though.
Put the headlights/parking lights on - blinkers won't work? All the parking lights work. 1157s (1156) went in the back. Blinkers weren't working at all before the new bulbs.
Thoughts?
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What bulb did you use? You indicated 1157 and then (1156). You need to use 1157.
Go to 8-76 in the service manual. It lays it out pretty well.
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1157 - just checked the pack ... and now I went out there and they work (sort of) with the parking lights. Really slowly. Then the right side stopped.
I've a mix of 2009 bulbs with 1976 bulbs.
Resistance issue?
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I would start by replacing the old bulbs. The bulb provides a ground path for the side market to blink.
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I swapped out all of the rear right-hand side lights - still has issues. I need some more bulbs to replace the left side ... that said, I'm seeing a voltage drop via the voltmeter in the dash that coincides with the blinker "firing" .. mmmm.
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Have you gone through the diagnosis in the service manual?
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I don't have the service manual ... I'm a slacker.
The manual timing works if I'm out at night - you know, lowering your index finger every second. Other than that, everything seems fine as far as exterior lights.
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Do your hazard lights work?
Also, tell me exactly what bulbs are not blinking with headlights on and with headlights off.
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Grabbed some new bulbs for the tail light assembly - snapped them in. The blinkers worked - I thought they were faster though.
Put the headlights/parking lights on - blinkers won't work? All the parking lights work. 1157s (1156) went in the back. Blinkers weren't working at all before the new bulbs.
Thoughts?
TRY the main round fuse for the lights /blinkers dave.
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Hazards work fine with or without the headlights on.
Blinkers run at half the speed of the hazards with the headlights OFF.
Blinkers tend to not illuminate with the headlights ON - both sides do this, front & rear will not blink.
Optima battery is putting out 12+ volts ...
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Check the flasher. Does it make a noise when the headlights are on? It might be defective.
Pull one from one of your cars that doesn't have issues.
You have some great looking cars.
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The round fuse in the top left of the panel clicks when the blinkers are on. Seems louder than it was before.
With the headlights on, it doesn't click unless they decide to flash - it's intermittent at best. Sometimes it'll flash, at least it did earlier in the day, but I couldn't get them to blink with the lights on.
The hazard lights must be on a separate line/fuse as they don't make the same noise. Much quieter, no difference with the lights on/off.
I'd pull the large round fuse from one of the 79's but they both have protective covers under the dash. The '76 is easy. I'll have to pull a car out in the morning if I don't want door dings. The garage isn't that wide!
(http://i288.photobucket.com/albums/ll178/jphillips3333/Y84/SE_BL.jpg)
(http://i288.photobucket.com/albums/ll178/jphillips3333/Y84/Intro.jpg)
Thanks for the compliment ..
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That's a hush panel covering the fuse box. Those usually get tossed the first time someone needs to get under the dash. My car didn't have one but I bought one and installed it. I think that was an option that came with more soundproofing. Beautiful cars.
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Thanks dude ... will "tear into it" tomorrow.
Not really ... I'll gingerly lower the hush panel and gently pry the fuse from it's home of 30 years hoping to not dislodge anything.
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check for a bad ground . you might have broken a wire at the bulbs when you changed them .
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I changed four bulbs .... I'm looking for a break in the wire at the back of the twist locks? OK ... I can do that tomorrow as well. If I find something, I'll solder it up or crimp a connector on it.
I don't think I'll find anything but I'll look - I say that because I didn't see any flickering or intermittent nature of the lighting. I pulled them out and checked them and checked them back in the tail light assembly.
As background, they didn't work at all when I started this and now I'm at the point where everything lights up, everything works ... except if the parking lights and/or the headlights are on.
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well the wiring is over 20 years old , and atleast I didn't say you where out of blinker fluid ... :o ;D
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Changed the flasher - no joy. Asked for blinker fluid at the store - they were out but were ordering from some guy named Stimpy who bounces around waving one hand. I don't know what the other hand is doing and really don't think I want to know... ;)
So, I'm leaning towards the short theory at this point ... but I'm going to get some sandpaper on the sockets ... it is Florida afterall. Decreasing resistance increases flash rate. V=IR ..Ohm's law .... off to hunt rust.
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Have you changed the front bulbs? The parking light bulbs?
Check the turn signal fuse. (although I'm not hopeful on that).
If none of the above work....you've got a wiring problem. And that's a SOB to find. It could be a ground issue or something in the turn signal switch. Turn signal wiring is a black haze to me, I don't understand it very well.....no probably not at all.
There is a clue however. Let me repeat the problem
1. The turn signals work fine when the headlight switch is off.
2. You turn the headlights on and the turn signals no longer work.
Easy enough :P
The only difference is that pesky brown wire from the headlight switch. That wire doesn't enter into the picture unless the headlights are on. So, I would measure voltage at that brown wire. I think that could be where the problem lies.
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Never touched the front bulbs or side marker bulbs (front or rear). They all work.
#1 - yes, however slower than normal. Repeat rate if you will.
#2 - yes, they don't illuminate. I can manually tap down on the stalk to force the turn indicators on at night.
Brown wire ... where should I start? Switch behind dash/inst. cluster, fuse panel ....out to the headlights?
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The brown wire is on the headlight switch. It goes to the rear of the car into the bulb socket. And also to the front of the car through the bulkhead connector to the parking light bulbs.
But the front bulbs don't blink when the headlights are on right?
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Correct - no blinking anywhere with the headlights/parking lamps on.
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Correct - no blinking anywhere with the headlights/parking lamps on.
It's got to be that brown wire. Check that for voltage. And check your grounds.
It can't be the turn signal switch because they work with the headlights out. You still could have a bad bulb though.
I hate working on turn signal problems. They usually end up being something simple too.
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ha ha funny John , you order the blinker fluid from here ;D ;D http://kalecoauto.com/index.php?main_page=products_all
I would check the bulbs with a multi meter to make sure you don't have one thats shorted internally ( have run across a couple of these before especially with the cheap bulbs you get at the cheap auto parts store ) then I would also check the headlight switch to see if the switch might be shorted internally , Now on someof the older cars they used to use a diode in the column (76 earlier ) , But I don't remember seeing one when I take columns apart for the later models so they might incorperate it into the headlight switch , and when you clean the light contacts in the back put dielectric grease on them to keep the moisture out also theres a ground wire in the trunk harness up by the package tray that sometimes gets ripped off . also check your body ground for the battery
as for stimpys other hand its on the keyboard .
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Stimpy's right about the bulbs. They're a PIA and have had me fooled more than once. By the way, I believe the grounds are on either side of the latch....in that area anyway.
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Thanks -
To do:
Check body ground for the battery
Check the grounds up around the trunk release
Run some sandpaper over the contacts in the rear light sockets.
Check the contacts with the multimeter when "blinking"
Brown wire on the rear driver side run to the bulbs?
Headlight switch - easiest way to get to that is to pull the trim rings, instrument cluster, etc?
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Yes on the headlight switch.
But don't forget the grounds under the hood for the lighting harness either. There should be one on either side of the core support above your side marker lights. You might want to check that those are intact and actually have a good ground. When in doubt, run a test lead from the battery ground to the core support. I just ran another ground - 4g - to the core support from the battery and cleared up a host of ground issues. And its not like I don't have a serious grounds to begin with....
Battery ground - 4g cable to engine block
Engine block - ground strap to bulkhead connector (I added this - drilled hole in firewall for it).
Bulkhead connector - 4 gauge cable to emergency brake mechanism inside car.
From the emergency brake ground I ran two 14g grounds up to the dash area and two 14g grounds to the doors. From the bulkhead connector is the ground to the stereo.
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I checked the battery ground - it's clean, corrision free. Seems to have a good path to the block ... ARP head bolts don't let me attach to the heads but I'm on a bracket. Altered that to another clean location, no difference.
Trunk Grounds;
I replaced one of the grounds is the trunk ... had a couple strands of wire loose. No corrosion.
Parking lights;
I checked the voltage to ALL of the rear trunk bulbs - 11.1 volts to every main rear bulb for the parking lights. Used contacts inside where the bulb sits in the housing and used the trunk ground for a reading as well as against just the wires leading into the bulb plastic housing. Same reading for both measurements. Brown/Black wires.
Blinkers;
Checked the blinkers driver (yellow) and passenger (green) wires against the turn indicators. ~8 volts, dropping to ~2/3 volts. Used the wires leading into the bulb housing. Green/Yellow and Black wires.
Front side marker grounds;
Remove, scuffed, PB blast, reattached. No wiring looked disturbed. Slight corrision.
Front turning indicator bulbs;
Replaced for good measure.
NO JOY.
The 8 Volt reading is odd - I think I should see 11/12 volts at the rear wires when the blinker flashes.
Thoughts?
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This may be way off but how does the turn signal lever hang, is it lose and sags down? I have had a turn signal cam cause the problems you describe in a Bronco. If you have someone center the tuen signal lever does that make the lights come on? Hey it is worth a shot
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Do the volts differ at the yellow and green wires when you have the headlights on versus when they're off?
What causes the voltage drop is resistance. So, you'll need to work your way back from the blinkers to the switch, measuring the voltage at every point available to try to isolate where the drop takes place. The bulkhead connectors could have corrosion. Or, as ta6point6 indicated, it could be a bad switch.
But, I'm not sure that correcting the voltage drop will fix your problem. It might. I think they need a college course on blinkers. ;D I'd sign up for it. The lab might be frustrating though.
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Pull the headlight switch its shorted . it should be 12.8 v when running 11.5 or so on battery . the hazards go thru the turn signal switch so the problem isn't there ( you could double check by measuring at the connector at the base of the column ) will read infinate .
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Yep ... I'm thinking that too Stimpy. The turn indicator lever is fine - it's not loose, no effect on the lights. I was just digging around the forum for bezel removal instructions - might hit that this weekend time permitting.
Russ - I'll check the voltage with/without the parking lamps on tomorrow ... I called it quits at 11:00 on lights today.
Changed a cork valve cover gasket in the SE yesterday. Took both of the '79s for a walk after lunch.
I changed out the exhaust gaskets on the '76 - put the RemFlex gaskets on around 3:00. They snugged down nicely so I don't think I'll have that tick anymore.
It's been a busy spring break.
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to remove the headlight switch reach under the dash and you will find a steel pin button( with a spring ) push this in and pull the switch Knob out ( you might want to disconect the battery wire first as it sometimes turns the lights on ) sometimes it helps to push the Knob inalittle then pull it out as theres a notch in the shaft your trying to get the release out of . pull the shaft all the way out and then use a wide flatblade screwdriver to loosen the retaining ring ( righty tighty lefty loosen ) then the switch will drop out of place then unplug it 2 clips on the side ) take it with you to get the right one ( have gotten so called right ones that were wrong ) then reattach the electric plug , and reverse the removal procedure when you push the Knob back in sometimes you have to push the steel release pin in to get it to lock to the shaft . I recommend some knee pads as you will apreciate this afterwords .
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to remove the headlight switch reach under the dash and you will find a steel pin button( with a spring ) push this in and pull the switch Knob out ( you might want to disconect the battery wire first as it sometimes turns the lights on ) sometimes it helps to push the Knob inalittle then pull it out as theres a notch in the shaft your trying to get the release out of . pull the shaft all the way out and then use a wide flatblade screwdriver to loosen the retaining ring ( righty tighty lefty loosen ) then the switch will drop out of place then unplug it 2 clips on the side ) take it with you to get the right one ( have gotten so called right ones that were wrong ) then reattach the electric plug , and reverse the removal procedure when you push the Knob back in sometimes you have to push the steel release pin in to get it to lock to the shaft . I recommend some knee pads as you will apreciate this afterwords .
You shouldn't have to push that pin on the headlight switch. That little headlight switch bezel should be installed prior to installing the dash bezel. The proper installation will have the dash bezel over that headlight switch bezel. Some people get that screwed up and install the headlight switch bezel AFTER installing the dash bezel.....not good.
Also, that headlight switch has the plastic light path installed on it. They used a plastic pin that pushes in for easy installation......and very hard removal. You should be able to work the headlight switch out without removing that plastic light path though. But take note of that because they almost always get broken...the other end sticks into a slot on the cluster.
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I think I figured out how the blinkers work. The parking lights have three wires, black (ground), blue (blinker power), brown (headlight switch power). The side markers have two wires, brown (headlight switch power), blue (blinker power).
When the blinkers are activated without the headlight switch on.....there's power to the blue wire an no power to the brown wire. The side markers get ground from the brown wire. The flasher interrupts the power by alternating ground/unground (I think this is right).
When the headlights come on, the side markers get power from the brown wire and use the blue wire as ground. When the blinkers are activated, the side markers have power to the blue wire and power to the brown wire. When that condition is present, the flasher is activated and interrupts power to the blue wire and grounds that. The side markers go on and off with the flasher.
Now the parking lights, when the headlight switch is off, the side markers and parking lights blink together. The parking lights use the black wire for ground, while the side markers are grounded via the brown wire.
When the headlight switch is activated, the brown wire is powered. This turns on the parking lights. Since the parking lights get ground from the black wire, when the blue wire is powered by the flasher, the parking light blinks. When the parking light blinks, the side markers are in the off sequence. This is because when the blue wire is powered with the headlights on, the side markers lose ground
Whew! It took me a couple of hours to figure this out....but it's really quite simple.
Let me know if I'm totally wrong about this.
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you have to remove the knoB and the only way your going to remove the knob is to push the pin in as the switch is held to the metal frame of the dash assy with the bezel screw ( theres a outer trim peice and a inner one that hold the switch to the dash frame )
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Got called into work this morning - not much time to get to this.
Russ - I think you're absolutely dead on with the writeup on the turn indicators. Roll in the green/yellow vs. brown wire in the rear and you've got everything covered.
I'll be doing the bezel this Saturday morning. I'll stuggle but have the dash removal page on the site to help me stagger through it. I've also got a 160 MPH speedometer I might try to sqeeze into the car while it's apart. Hopefully that's straight forward.
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you have to remove the knoB and the only way your going to remove the knob is to push the pin in as the switch is held to the metal frame of the dash assy with the bezel screw ( theres a outer trim peice and a inner one that hold the switch to the dash frame )
No, the knob doesn't have to come off unless the headlight bezel has been incorrectly installed. The dash bezel slips over the knob without removal. You do nothing with the headlight switch when you remove the dash bezel.
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You have to remove the bezel to get to the switch (and the speedometer).
The headlight switch unplugs from the bottom. Once you remove the screws, you need to rotate the headlight switch 90 degrees counterclockwise to slide it out. I don't think the knob has to be removed - it goes with the switch according to the photos?
http://www.78ta.com/resto/rdash.php
Guess I'll find out Saturday.
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John,
No the knob doesn't have to be removed. And, the more I think about this the more I believe your headlight switch is OK. Are you sure you swapped the directional signal flasher and not the hazard flasher? I think you've got a bad directional signal flasher.
The only way for the lights to stay on is if the directional signal flasher isn't working properly. The directional signal flasher is not on the fuse box. It hangs near there though. It should have a double pink wire with a black stripe, and a purple wire. The connector is red. Try swapping that one. My guess is that's your problem.
I was stumped until I figured out you probably swapped the wrong flasher.
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I pulled a silver one in the fuse panel made by Ideal Corp - HD 552. I replaced it with a two terminal thermal flasher - same 552 part number
I just pulled the one attached to the pink/purple wire with the red connector - it has that yellow housing. It's also a two terminal (L-shape).
Is there a difference? Reason I ask is I recall the guy at the parts store showing me a yellow one and stating something to the effect that they're the same thing.
I measured 46 ohms across the removed silver HD 552, the yellow has .7 ohms.
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Yeah, the one with the red connector is the one to swap. I'm not sure on the part number....but that flasher does have a yellow cast to it.
You won't hurt anything by lighting that new flasher up....live a little! Give it a try.
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BINGO ... we have a winner!!!!
I took your advice and "lived a little". Slapped the old silver HD 552 in place of the yellow one attached to the pink/purple wire with the red connector and Bob's your uncle. Repeat rate is there, lights on, brake lights ... it's ALL glowing now ... the planets have aligned.
They are interchangeable per the parts guy comment - the yellow one was bad per the reading above. I'd replaced the wrong one in the fuse panel back on page one. The fuse panel holds the hazard flasher, the pink/purple wire the directional flasher. Your guess was right - I pulled the wrong one.
Thanks dude ... this should be a blinker stickey - lot's of good info for folks to chase down.
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You made me work on this one! Now blinkers aren't the black hole for me anymore.
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Hi, I'm having a very similar problem, I replaced the turn signal flasher, that helped but when I pull on the lights the left signal indicator on the dash comes on and the left front signal and left marker are off. When I turn on the left signal it works but slower than the right one. The hazards are fine. When I look close at the left signal light when its flashing , the wrong element is flashing. Compared to the right one.
Confused yet? on the right sgnal/parking light 2 elements are working but the short one is blinking, on the left only the long one is blinking.
could it be the headlight switch?
Thanks in advance for any info.
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Sounds more like a short to me. Any chance you have the steering column bracket off? I believe that grounds dash.
Also, did you check the bulbs and sockets to make sure there not all cruded up?
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I checked and changed the bulbs, they are OK, no I don't have the steering column out.
I'll have to get someone to help me check for a short.
Thanks for replying.
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My car did the exact same thing when I bought it. I don't remember exactly what the fix was, but I know that between changing the flasher, replacing one bad turn signal socket and cleaning all of the electrical connections my lights work perfectly now. By process of elimination, you'll eventually find the cause.
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found it, it was the connector at the wire harness end of the signal light socket, it wasn't fully pushed on to the other connector.
thanks for the assistance.