Hitman's Pontiac Trans Am Forum

Trans Am Information => Trans Am Tech => Electrical => Topic started by: 79 Rebel on March 06, 2009, 09:42:47 AM

Title: New Cluster Question Merged
Post by: 79 Rebel on March 06, 2009, 09:42:47 AM
my 79 had a 81 cluster
my new 79 cluster will be here today
will the plug in fit

[attachment deleted by admin over 60 days old]
Title: Re: will the plug in fit 79 cluster
Post by: OrigOwner77 on March 06, 2009, 10:39:55 AM
The plugs are all the same as far as I know. What we need to know is the wire colors and locations in the plug that's in the car. Then compare that to the service manual diagram for the cluster wiring to see if it matches up.
Title: Re: will the plug in fit 79 cluster
Post by: ta78w72 on March 06, 2009, 02:51:46 PM
That doesn't look right.  Give us the wire colors by pin number.  The pins are numbers on the white connector.  You may have a non rally harness.
Title: Re: will the plug in fit 79 cluster
Post by: Joker (§ir£Ğragon) on March 06, 2009, 03:21:35 PM
No, that's the right configuration for an '81 according to the diagram that Hitman posted here. http://www.78ta.com/smf/index.php?topic=13791.msg144431#msg144431

But if you go back to that thread and compare the two diagrams he gave you you'll answer your own question. the connectors are the same, but the wiring layout is completely different.
Title: Re: will the plug in fit 79 cluster
Post by: ta78w72 on March 06, 2009, 05:02:36 PM
No, that's the right configuration for an '81 according to the diagram that Hitman posted here. http://www.78ta.com/smf/index.php?topic=13791.msg144431#msg144431

But if you go back to that thread and compare the two diagrams he gave you you'll answer your own question. the connectors are the same, but the wiring layout is completely different.

Be careful Larry, that first picture is of an 81 without rally gauges.  When I said it didn't look right, I was responding to his assertion that his car had rally gauge wiring.  That's why the wire colors and pin locations would be very, very helpful.
Title: New Cluster Question
Post by: 79 Rebel on March 06, 2009, 09:07:10 PM
got my new cluster today
put it in
and well i like it but there are a few problems of course lol..

1.the right turn signal light does not work instead it flashes the bright light : lights

after awhile of driving with the new cluster the fasten seatbeat light and brake light finally came on
brake light remains on though

dahs lighst were not working at night but after driving ten mintues the speedo light did come on
but no tach light ir center light for the water and oil pressure
what still could be causing this WHAT WIRE

im guessing everything is taking time to work due to the fact that it has sat so long the cluster

also the speedo does not have a clip on the back where the cable plugs in
is this normal

Title: Re: New Cluster Question
Post by: ta78w72 on March 06, 2009, 09:55:04 PM
Like I said in the last thread, we need to know the wire colors for each pin in that connector.  And, it would be really nice if you would post a picture of the back of that cluster.  Your wire's are in the wrong slots for your cluster.  I bet a bunch of other stuff won't work too.  Until you do this for us, we can't help you.
Title: Re: New Cluster Question
Post by: Joker (§ir£Ğragon) on March 07, 2009, 12:41:06 AM
And please try and keep things relating to the same issue in one thread. this is getting confusing having to go and search the old ones to see what has and what hasn't been done.
Title: Re: New Cluster Question
Post by: 79 Rebel on March 07, 2009, 12:49:29 AM
well geez i guess this is lecture me day
Title: Re: New Cluster Question
Post by: Joker (§ir£Ğragon) on March 07, 2009, 01:16:50 AM
Sorry, We're not trying to be nasty. It's just hard to follow things when it's stretched between so many threads. And we do need to know (or better still - see) those wires. Once we know where each wire is now one of us can tell you where they need to be.
Title: Re: New Cluster Question Merged
Post by: Hitman on March 07, 2009, 11:06:39 AM
I tried to merge the topics, but don't know if that worked too well.
Title: Re: New Cluster Question Merged
Post by: 79 Rebel on March 08, 2009, 10:58:49 AM
well ive decided im just gonna leave it the way it is
the only problems are
instead of turn signal the high beam light flashes
and the tach light doesnt work but speedo light does
im not gonna full with it

should the back of the speedo have the clip or no
because it doesnt
Title: Re: New Cluster Question Merged
Post by: OrigOwner77 on March 08, 2009, 05:46:22 PM
well ive decided im just gonna leave it the way it is
the only problems are
instead of turn signal the high beam light flashes
and the tach light doesnt work but speedo light does
im not gonna full with it

should the back of the speedo have the clip or no
because it doesnt

The back of the speedometer is supposed to have a clip to hold the speedometer cable on.

And, you can leave the incorrect wiring on your car if you like. You're the one risking problems (including risk of a fire) caused by incorrect wiring though...so if you're willing to risk that, then leave it. Personally, 5 minutes to take a picture and type what wire colors are where on your connector is a lot smarter in my opinion though...but to each their own I guess. :? Good luck!
Title: Re: New Cluster Question Merged
Post by: 79 Rebel on March 08, 2009, 09:56:23 PM
well once i take the picture and see the wire locations
is it easy to relocate the wires
i mean can you guys help me ?

and i guess i will have to take the clip off my old cluster for the speedo cable
i would love the help you guys are willing to help me

i dont i know what wire is in what location when i look at it
Title: Re: New Cluster Question Merged
Post by: ta78w72 on March 08, 2009, 10:14:46 PM
Just swap speedo's.  As for the wires, we'll tell you how to change the locations if necessary.  The white cluster has numbers on it if you look closely.  Just tell us the color of wire that corresponds with each number.  With that information and a picture of the back of the cluster, we can tell you exactly what you need to do.
Title: Re: New Cluster Question Merged
Post by: 79 Rebel on March 08, 2009, 10:24:06 PM
ok sounds great
tomorrow
i will do it
Title: Re: New Cluster Question Merged
Post by: OrigOwner77 on March 08, 2009, 10:45:32 PM
Just swap speedo's.  As for the wires, we'll tell you how to change the locations if necessary.  The white cluster has numbers on it if you look closely.  Just tell us the color of wire that corresponds with each number.  With that information and a picture of the back of the cluster, we can tell you exactly what you need to do.

Exactly...except for swapping speedometers. I believe the OP has an 85mph unit on the old cluster (80/81-style), and has purchased the correct 100 mph unit. Can the clip be removed from the old speedometer and placed on the new one? If I recall correctly, it can. I *believe* it just (pardon the term) clips to the speedometer.
Title: Re: New Cluster Question Merged
Post by: 79 Rebel on March 08, 2009, 10:51:29 PM
thats what im thinking
i think it will slip right on
because yes this is the correct cluster now 'i noticed the speedo works great but somethings when hits 20 it has to catch up
i think thats because the clip is not there to keep it secure
Title: Re: New Cluster Question Merged
Post by: OrigOwner77 on March 08, 2009, 10:57:36 PM
It could be jumpy if the cable isn't properly seated. The cable could also need lubrication. I believe white lithium grease has been suggested before - just spray some in each end of the cable (speedometer-end and transmission-end).

Not to scare you, but I have had a speedometer go bad mechanically and jump. However, I gather this is a rarity and would believe your issue to be related to the cable not being secured.

Try swapping the clip over and seeing if that helps first.
Title: Re: New Cluster Question Merged
Post by: 79 Rebel on March 08, 2009, 10:59:07 PM
ok
yes it works great
nice and steady
but sometimes when you floor it
it stops and 20 then catches up
i think it neeeds to be secured
Title: Re: New Cluster Question Merged
Post by: mattoree on July 08, 2017, 09:51:44 PM
Hey guys. Just joined here on the forum. Happy to be here. Got a question for you all. On my 1978 trans am, my speedometer is incrementally off. As in the faster I go, the more its off. Around 70mph on my gps, and the speedo reads 65. And it obviously gets worse the faster I go. I have changed the cable as mine too was melted by the exhaust. Although it was off before the cable melted. After I replaced the cable, its still off but does at least work again. I actually used it as an excuse after getting pulled over for speeding. Ha. Any thoughts on what it could be? Anybody have this problem? Any help would be really appreciated. Thanks
Matt
Title: Re: New Cluster Question Merged
Post by: Aus78Formula on July 09, 2017, 12:37:21 PM
Nothing to do with cable or being melted or speedo fault, simply rear gear ratio does not match speedo gears in gearbox. Or by the sounds of it in your case, the tyre profile has been changed to something slightly taller than stock so it is going slightly faster than it thinks it is. Easy to fix if you want to, just depends on the combinations of above. Not sure they'd accept that excuse for speeding, more than likely they'd start to look around and find other faults.
Also, headers can be one thing with the speedo cable melting the sleeve, make sure the retainer is in place that holds it off as well, on inside of chassis rail.
Title: Re: New Cluster Question Merged
Post by: mattoree on July 09, 2017, 06:56:02 PM
thanks! Yes, I have headers and no cats. At the time I had them installed, shortly after the cable melted. I replaced that but the speedo has been off since I bought the car in 2007. I thought the car was a ws6, but turns out someone just upgraded the wheels to 15x8 probably sometime ago. That being said, that's just a wider wheel. I'll have to check the tire size that's on it now to see how different it is than a stock size. How would I know what gear to change it to? Where is the gear located? According to the code on the rear, it has stock 2.56 gears unless they have been changed, but I don't think so.
Title: Re: New Cluster Question Merged
Post by: Aus78Formula on July 09, 2017, 09:58:25 PM
Assuming all the gears and diff ratio are standard, the speedo gears for 2:56 should be a Red 17-tooth Drive gear and a Light green 34-tooth driven gear. That was one of the common combos, based roughly around a 26-27" diameter tyre. Blue 18/White 35 tooth is also another combination used..

Here's some handy links, one to a calculator once you know your tyre diameter. The other is a handy shop of parts. Remember that the BOP TH350 does not use chev TH350 gears, but the TH700 type. This is not often made clear in shops and ads who only chev.

http://www.bgsoflex.com/speedo1.html

https://transmissioncenter.net/shop/700r4-driven-gear/
Title: Re: New Cluster Question Merged
Post by: mattoree on July 09, 2017, 11:40:41 PM
oh super cool. Thanks for the info! Much appreciated. My trans is the 400 turbo. Just checked, my tires are eagle good year 255 60 R15. So the stock ones should of been 70 series. I guess that's where the problem is. So I'll have to change the gears then. How hard of a job is that?
Title: Re: New Cluster Question Merged
Post by: Aus78Formula on July 10, 2017, 12:22:48 AM
A 255/60 will be similar diameter to a 225/70. The fact you have a non-original th400 means it prob has anything for the speedo gears. Unplug the cable and shine a torch in can at least tell colour or housing type. That is If you have a th400 and not just a previous seller saying so.