TAC Tech => Electrical => Topic started by: pozarcar on January 04, 2024, 01:27:19 PM
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I'm going through the wiring under the dash of my 78 TA trying to neaten up. On the driver's and passenger's side of the dash there are a set of orange/black and white wires that look snipped off. No connector. The wiring diagram says they are for courtesy lights, which make sense with the location. Does the fact they dead end mean my car didn't come with that option, or think somebody snipped them out?
Also, I found an unconnected connector with an orange wire and a black wire. The wiring diagram shows a connector with those color wires labeled "digital clock". I don't think a digital clock was offered in Firebirds in 1978, but maybe an unused connector in the harness that could be used for other cars???
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Orange/black white is for the courtesy lights. Yours have been snipped.
The brown and orange connector on mine was never connected to anything.
According to Hogheads Trans Am page it was used, starting in 1980, for the digital clock in the stereo.
Halfway down the page: https://www.firebirdtransamparts.com/techinfo/harness/harness.htm
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Thanks! I will also post in parts wanted, but if anyone has a set of the courtesy lights to sell send me a PM.
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I 2nd wheels’ explanation.
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Those plastic light sockets you're missing are on many GM cars from 70-80's. Especially in luxury cars. Got mine out of a junked 86 olds Cierra for free.
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My 1980 TA came without under dash courtesy lights and a glove box light. Unlike your car there was no wiring for the courtesy lights. One of TAC's most prolific posters (Wallington) came to the rescue with an eBay listing with the lights and bulbs and harness. All I had to do was plug into my existing harness next to my glove box. It appears you already have the wiring and just need the sockets and bulbs. I would take a DVM and meter across the orange and white wire to verify you get 12volts when one of the doors are open. Then you can purchase new aftermarket kits from almost any restoration supplier, as in the pictures
(https://live.staticflickr.com/65535/53474328455_4c13b51653_k.jpg) (https://flic.kr/p/2ptkUQg)IMG_4036 (https://flic.kr/p/2ptkUQg) by Lawrence Alexander (https://www.flickr.com/photos/188552644@N06/), on Flickr
(https://live.staticflickr.com/65535/53474054618_35d1fafafc_k.jpg) (https://flic.kr/p/2ptjvqW)IMG_4037 (https://flic.kr/p/2ptjvqW) by Lawrence Alexander (https://www.flickr.com/photos/188552644@N06/), on Flickr
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I didn't work at GM, but I figure that "digital clock" wire showing up on the 1977 diagram must mean they were thinking about adding another style clock to the dash, but they just changed their minds. Oldsmobile did a ton of them in the 70's and those were not what you'd think of when somebody says "digital clock"
You'll also see a reverse light wire coming from a 5 speed transmission on that 77 diagram. At the time, that would have been the Borg T-50 or what you'd recognize as a transmission out of a sunbird. Again, Oldsmobile actually built them. They built 1977 cutlasses with a 5 speed manual. Omega as well. Some with the 260 V8 I believe.
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I didn't work at GM, but I figure that "digital clock" wire showing up on the 1977 diagram must mean they were thinking about adding another style clock to the dash, but they just changed their minds. Oldsmobile did a ton of them in the 70's and those were not what you'd think of when somebody says "digital clock"
You'll also see a reverse light wire coming from a 5 speed transmission on that 77 diagram. At the time, that would have been the Borg T-50 or what you'd recognize as a transmission out of a sunbird. Again, Oldsmobile actually built them. They built 1977 cutlasses with a 5 speed manual. Omega as well. Some with the 260 V8 I believe.
I thought digital clock plug started showing up on the 78 manual. I have the trans switch shown but not digital clock plug.
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I had a short that affected the circuit the courtesy lamps and clock are on, and after fixing that, replaced the original clock with a quartz movement one from Classic, and after a bit of modification to the new clock's housing, it has been perfect - if you have more questions about the circuit, feel free to reply - I spent days on figuring out the whole circuit!