89’ pink/black and purple wire

[scoots90245]

It looks like there was a switch here, but there’s also a spot on the back of the brake switch to plug it in. Pink and black wire hot with ignition on. Try to figure it out myself cruise control, brake light schematic and I’m failing miserably. Please help.

 

[nvrenuf]

What year?

 

[scoots90245]

1989 air conditioning, power windows, cruise control

 

[scoots90245]

Most of the cruise control stuff has been taken out

 

[scoots90245]

I was able to find too many pink and black wires related to cruise control and brakes, but nothing with the purple wire combination

 

[nvrenuf]

Purple is used in the neutral safety switch circuit, iirc.

 

[scoots90245]

Should that have its own switch or should that be plugged in to the back of the brake light switch?

 

[scoots90245]

Purple is used in the neutral safety switch circuit, iirc.

Thanks

 

[nvrenuf]

Yeah, it's usually got a female 2 terminal black connector, it's been a long time since my harness was complete with cruise stuff so I can't remember if it runs through the brake/cruise switch.

 

[Wes Harden]

Brake lamp switch wiring will be hot all the time. That might be related to 700r4 torque converter lockup. Which you don't have.
Neutral safety switch will be 2 12ga purple wires in a flat 2 wire plug, that plugs into switch at base of steering column, in cab.
This switch will have second set of terminals for the reverse lamps

 

[scoots90245]

Brake lamp switch wiring will be hot all the time. That might be related to 700r4 torque converter lockup. Which you don't have.
Neutral safety switch will be 2 12ga purple wires in a flat 2 wire plug, that plugs into switch at base of steering column, in cab.
This switch will have second set of terminals for the reverse lamps

Excellent info I will make sure neutral safety and reverse lamps are working tomorrow.
I do have the 700R4 but the guy who did the transmission put an adjustable B&M lock up switch in.

 

[Wes Harden]

The empty spot your finger is pointing to is for the 700r4 vacuum switch, this switch was used to signal the unlock for the torque converter. You no longer need, with the B&M kit.

I am curious how the brake on signal works with current set up. Also make sure it still works after you finish your wiring. Never know if the installer tapped in somewhere and your new loom will eliminate that tap.

 

[scoots90245]

The empty spot your finger is pointing to is for the 700r4 vacuum switch, this switch was used to signal the unlock for the torque converter. You no longer need, with the B&M kit.

I am curious how the brake on signal works with current set up. Also make sure it still works after you finish your wiring. Never know if the installer tapped in somewhere and your new loom will eliminate that tap.

The brake switch has two feeds one is plugged in from below an orange and WHITE edit wire. Then there is the one with pink blue and purple that looks like it could plug in also. It I didn’t want to fry any wires

 

[Wes Harden]

I still haven't figured out that plug you asking about.

Yes I see the switch has 2 connections. there 2 types of switches, one has both connections normally open, when press the brake pedal it closes both sides. The other switch has one normally open(brake lamp signal) and one normally closed (tcc lockup)

I am not sure you need that wiring pink with black is very common instrument fuse power circuit and is used in many places.

 

[Wes Harden]

I should clarify, I am not sure you need that plug. Since you have the B&M kit. I do think it might have something to do with TCC or it could be cruise control.

 

[scoots90245]

I will try all the lights brakes nuetral safety hazards reverse
if everything is working ill zip tie it out of the way
Thanks for your help nvrenf and wes

 

[scoots90245]

I found a ppl and pnk/blk wire with brake switch in this 89' GMC service manual.
No idea how to read the schematic
Its listed with the 700r4.

 

[Wes Harden]

Interesting, downshift control relay hmm.

The pink with black is default 12v power circuit for computer sensors and actuators. No surprise there.
Iwhat year is that manual.
Down shift control relay, is new one me, and is probably part of the vacuum and wot switch system the pre tbi, and ccc, needed to function.

 

[scoots90245]

1989 supposedly I can't even remember where i found this
3-100
3-103

 

[scoots90245]

Interesting, downshift control relay hmm.

The pink with black is default 12v power circuit for computer sensors and actuators. No surprise there.
Iwhat year is that manual.
Down shift control relay, is new one me, and is probably part of the vacuum and wot switch system the pre tbi, and ccc, needed to function.

Interesting my 89 had cruise control and overdrive I guess that’s why there are to spots for switches. The cruise control is gone. I’m curious what would the switch do for OD if the B&M is installed should I complete the circuit or leave it disabled
Doesn’t seem to make a difference but it is hot when ignition is on?
Thanks for the heads up on the reverse light/ neutral safety switch. Getting a new switch old is cracked