Dash Electrical Help - 1987 V30

[Evil Trailblazer SS]

I have been coming across more and more "weird" wiring issues with the truck performed by previous mechanics and I am lost on a few of them! Any help will be sincerely appreciated!!!

In the main dash harness coming from the fuse panel up to the cluster, this Purple w/White wire is just sitting dead, what is this for?


Under the dash below the stereo, this harness is just sitting wound up dead...What is it for?


Green wire at the Black connector on the ignition switch on the top of the steering colum. Why would this be disconnected and what is it for?


Right behind the headlight switch, this little yellow wire looks like it comes all the way from the warning buzzer module on the brake pedal over. It is not plugged into anything and I cannot find where it "should" be connected! Also, the black wire accompanying it leads up from the fuse panel area. It can plug into the ground distribution block on the upper driver side kick panel, but what may it be for and is that where it is supposed to go?

[Evil Trailblazer SS]

Also, the roof clearance lamps were wired as normal down the A-Pillar, but at the front speaker, someone spliced them and ran a speaker wire all the way to the front drivers side marker lamp next to the headlights. I know this is wrong, but where are they supposed to tap into the factory wiring?
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[hatzie]

The stock clearance lamps run direct to the headlight switch.

[Evil Trailblazer SS]

I just probably need to purchase a replacement wiring harness for the clearance lamps because the end that should connect to the switch has no connector or anything.
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[Mattman2010]

Originally Posted by Evil Trailblazer SS

Under the dash below the stereo, this harness is just sitting wound up dead...What is it for?

This looks to me like the connector that goes to the brake switch that is on the right side of the column. There should be a bracket up on the brake pedal that should hit the switch. Its tucked up in there.

Edit: It looks like you have a picture of the brake switch in the 3rd picture, it is the thing on the far right. Should plug into the back of that.

[Evil Trailblazer SS]

The brake switch is the same style connector, but the brake switch is currently connected and has an orange wire and a white wire as all diagrams say my truck is supposed to have for the brake light switch. So this is not where that connector goes, Purple and Pink w/Black wires. What is strange, no diagrams I've seen call for these two colors on ANY connector under the dash.

Also, the green wire that was cut at the ignition switch ends up looking like the off shoot of the coolant temp sensor. As it comes from the sensor, it splits, one to the gauge cluster and one to the ignition switch. I have no idea what it does at the ignition switch, since it will power/ground through the gauge and ground at the sensor itself.
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[Jonboy]

That connector may go to the other end of the brake switch, for the TCC clutch.

[motornut]

reading some haynes pages
yellow might be clutch related....was it manual tranny?
or air cleaner temp switch/air diverter valve/air controller?
drk green ac clutch?and ECM

[Mattman2010]

Originally Posted by Evil Trailblazer SS

The brake switch is the same style connector, but the brake switch is currently connected and has an orange wire and a white wire as all diagrams say my truck is supposed to have for the brake light switch. So this is not where that connector goes, Purple and Pink w/Black wires. What is strange, no diagrams I've seen call for these two colors on ANY connector under the dash.

I was just going off the connector. The only other thing I have seen that has used one of those connectors is the clutch switch, and it looks just like the brake switch. I have seen your build thread and have noticed that it was an automatic, so I am not sure.

[Evil Trailblazer SS]

The clear connector with purple and pink/black wires is for the cruise control release switch...some clown decided to put a different switch in that does not have the place to hook up this connector, thus the cruise control is not working...some people piss me off! But at least I am slowly sorting all of this out!
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[VetteVet]

The purple and white wire in my 88 to 98 schematic goes to the cluster plug at point 10 and comes from the distributor connector and the ignition module. I can't tell what gauge it is but yours looks to be 12. I don't have an 87 diagram but the 85 and 86 ones I have don't show that wire.

If the green wire to the key switch is the temp wire it may be there to test the temp lite bulb when the key is turned on but not started.
Sorry I'm not much help.

[motornut]

if the green goes to the block for temp could someone have cut and used the wire for an aftermarket gauge?
powered with key on?

found a couple of random pics of my 87 4X4 burb I scrapped ,prob won't help but ...

[hatzie]

Originally Posted by motornut

if the green goes to the block for temp could someone have cut and used the wire for an aftermarket gauge?
powered with key on?

Yes. This wire could've been cabbaged for an aftermarket temp gauge.

No it's not powered. The ignition switch grounds circuits 33 & 35 when it's turned to the start position. Circuit 33 TAN/WHT is the BRAKE warning light and Circuit 35 DK-GRN is the TEMP sender.

I'd solder and heatshrink the wire after verifying, with a DVM continuity tester, that it goes to the cluster plug, ignition switch, and temp sender.

[Evil Trailblazer SS]

Will be looking at that tomorrow! thanks guys!
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[Evil Trailblazer SS]

So can anyone answer me this riddle?

Why would someone remove the proper Cruise Control Release Switch and replace it with clearly the wrong switch?

- Proper switch that my truck is supposed to have -


-Wrong switch which was installed and NOT functioning as a Cruise Control Release Switch -

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