Hitman's Pontiac Trans Am Forum

Trans Am Information => Trans Am Tech => Electrical => Topic started by: Virginia T/A on April 20, 2009, 10:15:39 AM

Title: Electrical wiring diagrams
Post by: Virginia T/A on April 20, 2009, 10:15:39 AM

I know I have seen the wiring diagrams somewhere either on the post or on the CD I purchased, but I can't seem to find them when I need them. Can somebody please refresh my brain.  I am looking for the engine compartment / reverse light switch / AC and heater controls for a 1978 W72 / AC / 4 speed car. Someone has butchered my harness and I'm hoping I can figure it out instead of buying a replacement. Does anyone make a replacement harness for the engine compartment?

Title: Re: Electrical wiring diagrams
Post by: Joker (§ir£Ðragon) on April 20, 2009, 10:52:06 AM

I think there may be a few posted around here, although many people remove pics later to clear space. But they should be on your service manual CD.

Title: Re: Electrical wiring diagrams
Post by: ta78w72 on April 20, 2009, 10:55:09 AM

The A/C heater controls....I believe are in the A/C section....page 49 of the CD manual (electrical not vacuum).

The reverse switch...on the fold out pages.

Engine compartment...on the fold out pages.

I never use the CD for the fold out pages.  I have a couple original service manuals that I use.

Title: Re: Electrical wiring diagrams
Post by: Joker (§ir£Ðragon) on April 20, 2009, 11:05:58 AM

Here's a few not so high quality ones.

(http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/0f/0e/large/0900c15280080f0e.gif)

(http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/0f/1a/large/0900c15280080f1a.gif)

(http://econtent.autozone.com:24991/znetrgs/repair_guide_content/en_us/images/0900c152/80/08/0f/1c/large/0900c15280080f1c.gif)

Title: Re: Electrical wiring diagrams
Post by: RENOVATIONS on April 20, 2009, 12:11:31 PM

Quote from: Virginia T/A on April 20, 2009, 10:15:39 AM

Does anyone make a replacement harness for the engine compartment?

www.wiringharness.com

Title: Re: Electrical wiring diagrams
Post by: Virginia T/A on April 20, 2009, 12:47:40 PM

Thanks for the responc but I can't open the pictures.

Title: Re: Electrical wiring diagrams
Post by: Bhrojas09 on October 31, 2017, 06:59:14 PM

Are these the diagrams for the 1978 Tailights? My Tailights were working perfect and now only the blinkers work. Change the lightbulb about and made sure the cables are all wired up. I do have one brown wire hangin around but not sure if that's ground or if it's supposed to be hot. The Tailights stopped working once I got my ls2 swap on it

Title: Re: Electrical wiring diagrams
Post by: Wallington on November 01, 2017, 05:47:00 AM

Double-check all the usual things, bulbs, plugs and fuses. Here's the tail light wiring harness for '78. If you don't have the Factory service manual then get one.

And yes, brown is a live wire feed for park lights, brake lights and license plate lights. However, you should still have the flashers and the back-up lights if this brown wire is disconnected somewhere, assuming it's the main wire from the terminal before it branches out. Unplug the terminal pack that's mount on the trunk inner wall, turn on lights and see if you have power at that brown wire, follow it back in trunk harness if so.

(https://farm5.staticflickr.com/4504/24232148508_fcca786e4a_k.jpg) (https://flic.kr/p/CVj6vW)Firebird 1978 Electrical diagram 5 of 5 (https://flic.kr/p/CVj6vW) by Aus78Formula (https://www.flickr.com/photos/53057445@N08/), on Flickr