Topic: wiring mix up from battery??

[medicman]

Well I have ordered a new engine wiring harness from classic industries. They cost $130 that is taxes and delivery included.

[medicman]

I have power at the fuse box for the heater fan. The 3 prong resistor looks good on top of heater core under the dash. From the fuse box, where does the power go first, does it go to the resistor first and then to the fan switch or vise versa.

Thanks, Medicman.

[jjr]

 In researching this, there's not much on the no A/C configuration.

 Some areas seem to lend the thought that the relay is for the A/C
configuration only, but it's certainly not clear.

 What model year is this car?  I missed that somewhere, not that it
will make much difference in how it's wired, but in finding the info
maybe.

 Joe

[medicman]

The car is a 1979. it has a 455 with 400 6x heads from a ram air III. It has a holley dominator street intake and a holley 780 double pump carb.  The rear diff is a 10 bolt 3.73 posi from a 1970 ram air III.

Did I mention I bought a whole new wiring harness from classic industries, I hope will be here in roughly 7-10 days. The fella told me it was easy to install due to everything being labeled.


Thanks, Elliott

[ta78w72]

Well, it's possible that non A/C cars don't have a hi setting for the blower motor.  I'm just not sure but it wouldn't make sense not to have a high setting.  The way to tell is to make sure the motor runs on the lowest setting (always on), then move the lever up and each time listen for the blower motor to blow more air.  I imagine it does have a hi setting though.  You would want that for heat and defrost.  The hi setting bypasses the resistor (through the high blower relay) and directs current from the alternator to the blower motor. 

But the line from the alternator may be different for non A/C cars.  It might get direct power from the input to the fuse box.  So a special wire wouldn't be needed from the alternator.

But, if that harness from classic works out, it will be money well spent.  I don't like dealing with splices.  You're better off with a new harness.

[ta78w72]

I have power at the fuse box for the heater fan. The 3 prong resistor looks good on top of heater core under the dash. From the fuse box, where does the power go first, does it go to the resistor first and then to the fan switch or vise versa.

Thanks, Medicman.

It goes to the switch.  Then, the relay shuttles the current through the resistor.  The more resistance, the slower the motor....until the high setting which bypasses the resistor altogether.

[medicman]

I will look at that tomorrow, I have spent enough time in the shop today. (wife is going to shot me soon!!!)

[jjr]

 Well, the base wiring diagram does not show the relay, only the A/C section shows
the addition.

 Additionally, I think the non A/C control head has only 3 fan positions, whereas the A/C
version 4.

 No where that I can find does it directly address the issue.

 In my opinion, there's no relay in the non A/C setup, all the juice comes from the fusebox.

 Joe

[medicman]

I have been looking at my cd that I bought from the hitman, and it does not show very good wiring diagrams, It is a good cd but not great for wiring. Do you have any good easy to follow diagrams for under the dash. I just want to check every connection and the colour of the wire.

I have purchased a hard copy service manual from ebay but it going to take 14-29 days to get here.

Elliott

[jjr]

 While there is no substitute for the Pontiac service manual, they are
not exactly user friendly, quirky kinda.

 The wiring diagrams aren't exactly typical, nor easy to read, and I have
a degree in Electrical Engineering.

 About the easiest to do is to use the colors of the wires and the obvious
length match up. In rare cases I've had to trace back to the fuse box.

 Often GM used connectors that varied AND only fit one way, which helps.

 I thought your engine harness was the problem... which dash circuit(s) are
suspect?

 Joe

[medicman]

I believe the engine harness is most of my troubles ( the whole constant power thing is what is the worst.) I have learned from looking at the cd that there should be no pigtails off the + post of the battery and mine has two going in different directions.

When I looked under the dash, I found some homemade wiring (not alot but some) so I thought it best to test it all and make sure that everything is where it is suppose to be. I priced out a new dash harness and it is 700.00 I just about jumped out of my seat. Soooo, I am going to clean up the original one. I just want to rule out any gremlins that may come back to haunt me.

Someone on here ( I apolgize, I cannot remeber the person name)  sent me some wiring diagrams from a chilton manual and it is very nice and easy to follow, I wish Pontiac did the same thing.

What really sucks, is that I have nobody to come over and give me a hand. You know that old rule, two heads are better than one.

All my buddies I would not trust them with a screwdriver!!!!!!!!! But they are great guys and give the shirt of their backs if you asked

[jjr]

 Chilton never built any cars...

 Even though we can't come over, we can get the job done.

 Here's two pics that show "one" of the dash replacements I've
done.





 There's ample talent here to answer just about any question,
or get any part. I'd start watching ebay for the main dash harness
as I've found some for under $50. I kinda focus more on '80 and
'81 though, which are different.

 Here's a 1980 engine harness that I did a explanatory graphic on:



 I've done a lot of tech articles on various topics and am sure we can
get you back up to speed, right here on the forum.

 what do you think?

 Joe
 

[medicman]

WOW, I really appriecate the help, I am going to be printing off the pics and have them beside me when I am in the car working later today. I am quite sure there more than enough talent on this form to help me get my car running perfect in the end.

I hate bugging people that is my problem, I have had quite a few posts and I feel a little  embarrassed.

Anyways thank you for taking the time to help me out.  Is the last wiring pic you have posted the same as a 1979?

On your first picture, I noticed on the back of the plastic circuit board that you have one hole left unpluged (just below the speedo cable inlet) What is that for, and do you have  schematic of that piece so I do not accidently burn out the new one I ordered from classic industries.

[ta78w72]

Keep posting.  We like helping people.

That harness will differ slightly from a 79, but the basics are the same.

On the plastic film circuit, there are only four things that plug into the back of it.  The white cluster connector.  The tach connector.  The speedo cable.  And, the fiber optic light path for illuminating the ash tray.

There is also a plastic "light path" the connects in a slot in the drivers side of the cluster and is fastened to the bottom of the headlight switch.  This provides illumination to the wiper/headlight icon.

[jjr]

 Here lets' look closer...



 The open hole is where the lamp/optic line special plug
goes.

 You're not bugging anybody...

 I and many others have all been down the road you are traveling,
along the way I've photo documented some procedures and have
hundreds and hundreds of pictures.

 We want to hear and see the picture of you with your car after
it's all sorted out and working properly.

 The cluster's plastic circuit sheet is in the Pontiac Service manual, and
that particular illustration is very good.

 Next question?

 Joe