I need some assistance under dash around column

[Chevy3+3]

I pulled my column out and pedal assembly out and now I have 3 things I can't remember where they go. I'm up the creek without a paddle.

1. There's a rubber line (vacuum line?) that I obviously disconnected and can't remember where it went. It had to have been attached to the column or iny way at some point if I pulled it loose. Any ideas where it goes?

2. There is a black 2 wire connector with orange & white wire running to it. I'm assuming it goes to the brake light switch? But I also have a white/clear 2 wire plug with a purple & pink wire also under the dash hanging just right of where column sat.

I need help getting these things back where they belong. Any help is greatly appreciated. First pic shows the rubber hose. 2nd pic shows the pink & purple wired plug and 3rd pic shows the orange & whote wired plug. Thanks

[Wgesnerjr]

I think they all go to the brake light switch. 1 for brake lights, 1 for cruise control/lock up TQ. Rubber line bleeds vaccuum off curise control when brake is applied. Check the column. GM keyed their plugs so assembly line works could not mix them up. Should work in your favor too.

[Chevy3+3]

Well I figured out through wiring diagram that the orange & white wire plug goes to brake light switch. I already have the other plug for cruise control hooked up to brake light switch. So that still leaves me with the 2 wire plug with purple & pink wires. I am so confused because I know I disconnected the plug from somewhere but can't find any place to plug it back in.

As for the rubber line where does it attach? I'm almost sure I pulled it loose from something but can't find it either. Geez! This is frustrating because I usually don't have these kinds of problems when I work on things

[1968vetL-71]

Did ya convert this to a manual trans?
I did this to my old 91 crew cab, I had to clean up po's wiring messes from add ons under dash. time consuming!!

[Chevy3+3]

Originally Posted by 1968vetL-71

Did ya convert this to a manual trans?
I did this to my old 91 crew cab, I had to clean up po's wiring messes from add ons under dash. time consuming!!

I am in the process of converting it to a manual right now. I swapped out the pedal assembly. The problem is I know I unplugged the dang thing but can't find where to plug it back in. Im reinstalling the same column so it must not go to the column itself becasue I can't see any spots left to plug anything into

[Chevy3+3]

Ok I found out where the rubber vac hose ran to. Now I just need to determine where the 2 wire plug goes with the pink & purple wires

[hatzie]

Originally Posted by Chevy3+3

Ok I found out where the rubber vac hose ran to. Now I just need to determine where the 2 wire plug goes with the pink & purple wires

The two male terminals pointing straight down in that picture off a black box looks suspiciously like the right spot for that plug. The angled barbs are in the correct position for the catches too.

Read any numbers on that black module and look em up online. If you can determine what it is you can dig through the wiring diagrams to find what color wires are supposed to be plugged into it.

[Chevy3+3]

Originally Posted by hatzie

The two male terminals pointing straight down in that picture off a black box looks suspiciously like the right spot for that plug. The angled barbs are in the correct position for the catches too.

Read any numbers on that black module and look em up online. If you can determine what it is you can dig through the wiring diagrams to find what color wires are supposed to be plugged into it.

That's the brake light switch and it doesn't go there. It actually runs over to the left side of the column. I'm stumped!

[nonstop]

Could it for be a neutral safety switch? Was the truck always an auto?

[Chevy3+3]

Originally Posted by nonstop

Could it for be a neutral safety switch? Was the truck always an auto?

Truck was always an auto. After some info from another member we believe it is for the cruise control. I will check when I get home from work late tonight.

[hatzie]

Originally Posted by Chevy3+3

That's the brake light switch and it doesn't go there. It actually runs over to the left side of the column. I'm stumped!

Helps when I look at it on a PC and not a phone...

I was partly correct. That's a pedal switch type plug and it's not cruise control.

First. Cruise control...
Look at Page 309 of the 1988 wiring diagrams PDF for K34 Cruise control.

Since this was an Automatic truck there's only one cruise plug to the brake switch. It's already plugged in. It's got two wires. Gray and Gray with a Black stripe.

The Cruise Control cutout switch arrangement on a factory manual truck uses two pedal switches in series. The clutch switch would have the Gray with Black stripe wire that's in your brake switch plug and a short Brown wire from the brake switch position now occupied by your striped wire to the 2nd clutch switch plug cavity. I'd do it the same way.

Now for what that plug is... BTW you no longer need it for its' original purpose.

Your truck originally had the MD8 TH700R4 transmission...

Look on Page 294 of the 1988 wiring diagrams. TCC cutout control wiring to a brake pedal switch, for the MD8 transmission only, uses that connector with Purple and Pink wires.

Pink is Circuit 39 so it's hot with the ignition on. Purple is Circuit 420 to the TCC wiring plug on the TH700R4 that you no-doubt cut off the bulkhead plug in the engine bay.
You can repurpose the connector shell from the Purple and Pink wires for your clutch cutout switch for the cruise control or the clutch starter interlock switch.
Be darn sure to use some heat shrink that completely covers over the Pink wire terminal so it doesn't short and raise Cain with the electrical.
The purple wire goes to the bulkhead plug but there's nothing on the outside now.

Whatever that Scotchlok is for on the brake pedal switch white wire... get rid of it and tap into the wire the right way.

[Chevy3+3]

Hotzie your a wealth of info. Thank you. But.....my truck was a factory TH400. After further research on my end I am almost sure this plug was unused and tucked up above my factory auto pedal assembly. I could be wrong but another member just checked his '88 like mine and he to found this same plug unused high above his brake pedal

[hatzie]

Originally Posted by Chevy3+3

Hotzie your a wealth of info. Thank you. But.....my truck was a factory TH400. After further research on my end I am almost sure this plug was unused and tucked up above my factory auto pedal assembly. I could be wrong but another member just checked his '88 like mine and he to found this same plug unused high above his brake pedal

They must've included it with all AT cab harnesses.