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Old 10-20-2015, 11:08 AM   #1
LeesTruk
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TCC wiring question

I'm in process of under dash wiring for my LS swap, particularly the brake switch. I'm using a 3 position brake switch (1 n/o, 2 n/c ) from a '96 Firebird/Camaro. The 2 n/c switches will be for TCC and cruise. It's to my understanding that there will be B+ (ign. switched) to both of these switches and from the switches to the TAC (cruise pwr.) and the PCM for TCC. The question is, are these B+ sources for power or just 12v reference signals? Ultimately, the question comes to what gauge wire do I need to run?

I've got two neat factory pigtails that will plug into my fuse block. One looks to be 14 gauge, the other is 18 gauge wire. I'm not sure which to use for my wiring, although it would be safe to err on the larger of the two. Thanks

Lee
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Old 10-20-2015, 11:12 AM   #2
Hart_Rod
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Re: TCC wiring question

When in doubt, always go with the bigger wire.....
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Old 10-20-2015, 04:49 PM   #3
BR3W CITY
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Re: TCC wiring question

I have yet to see a tcc/tac/pedal/switch etc or any of those units fail or fire due to a wire being too thin...but that being said, I wouldn't want to be the first to find out! Most of the wire in "modern" assemblies is around 16. Cheapy parts and 5v electronics will see 22-18awg. Also mind that if your putting it into an old enough truck, you may have a large amount of solid-core copper wire, which has a different laod carrying capacity than braided strand wire.

Going from solid to braided repeatedly and jumping wire gauges can actually CREATE a problem where one wasn't before due to varying levels of current capacity and impedence.
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Old 10-20-2015, 05:11 PM   #4
LeesTruk
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Re: TCC wiring question

BR3W, my truck is an '80 and its' wiring is copper strand. I know the brake portion of the switch is meant to carry a "load" when applying the brakes for brake light illumination. I'm pretty sure the PCM supplies the 12vdc to the TCC, through the trans. harness (4L60E). What I'm not sure of, though, is if the PCM receives the 12vdc through the independent fuse block, or if it passes through the n/c portion of the brake switch. Am I right in thinking that the switch is just a "trigger" for unlocking the TCC when the brake pedal operation "opens" the switch? If that is the case, then the wiring won't be carrying a heavy amp load, much like the working of a relay. Yes?

Lee
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Old 10-21-2015, 12:19 AM   #5
BR3W CITY
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Re: TCC wiring question

Yes, its just working as a signal/trigger. Its all 12v, but the tail lamp circuit is pretty low amperage, less than 10iirc. The TAC and everything are individually powered, so its only using the switch for a "yes or no".
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Old 10-21-2015, 04:20 AM   #6
LeesTruk
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Re: TCC wiring question

Thank you, sir
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