M1008 with brake lights stuck on

[edman]

I have a 1986 M1008 with the brake lights stuck on. I assume the switch needs replacing. Can anyone tell me where the switch is located on the truck? I don't see it on the brake pedal and didn't see a hydraulic one in a line. Where is it?

 

[porkysplace]

On the brake pedal . TM9-2320-289-34p.pdf
SECTION II
TM9-2320-289-34P
page 125
FIGURE 49.
Item # 18

 

[Keith_J]

In a pinch, the switch can be taken apart, cleaned and put back together. Easily.

 

[edman]

Thanks for the replies but I still don't find the switch. Yes I had looked at the TM and can see it listed but it isn't there in the truck. I have changed them on other vehicles but cannot locate this one. I took off the lower dash panel and took a picture of the bracket where I believe it should be and as you can see it is empty. Is it in a different place on these trucks like on top of the steering column where it is hidden? Any ideas. Please help.

 

[dependable]

It is a pulnger switch, usually white, plastic, two wires. It is in contact with back of brake pedal lever, (curved metal bar that pedal is attached to). Not much to it and the same as lots of other cars and trucks.

 

[tailboardtech]

I believe the civilian trucks it is a orange wire and a white wire. They can push out of the bracket if they weren't installed correctly that is the right bracket for the civilian trucks. I'm not to keen on the cucv's wireing

 

[MarcusOReallyus]

edman, if I'm not mistaken, that bracket is where the switch should be. If so, where in the world are the brake lights getting switched?

I'm wondering if some past owner monkeyed the setup beyond recognition.

 

[edman]

Marcus, exactly. That is what I have been trying to get across to everyone. The whole pedal arm has no switch that I can see and there are no loose wires or unused plugs anywhere near the bracket in my picture. Where else could the brake lights be activated from. I know the brake lights were working up until they stuck on. I'm dumb founded.

 

[MarcusOReallyus]

Okay, way past my beddy-bye time, out under the moonlight, serenaded by our local frog chorus, I took some pictures. Cellphone pics, under less than optimal conditions, but I think they confirm my suspicion. You don't have a switch where the switch ought to be, which means it's been monkeyed.

Now you have some real detective work to do!

 

[MarcusOReallyus]

We're cross posting.

Maybe under the hood? Somebody installed a pressure switch, perhaps?

 

[tailboardtech]

Has anyone had the gauge cluster out lately? I beleve the wires come in from the top down so to speak I am wondering if it got pulled out and is hiding somewhere in that bundle of wires. In the pic it looks like where the switch hits the pedal it's shiny so it should be in there somewhere.

 

[edman]

Thanks all. Everything under the dash looks really clean and original. Other than the doghead relay mod I did. I guess I will need to carefully trace the wires and brake lines to see what I can find. I really like my truck and got to get this figured out. Here's pics of my children.

 

[MarcusOReallyus]

Nice! I like the desert camo!

Yeah, I think tracing wires is the only thing you can do at this point. Let us know what you find!

 

[Keith_J]

Okay, way past my beddy-bye time, out under the moonlight, serenaded by our local frog chorus, I took some pictures. Cellphone pics, under less than optimal conditions, but I think they confirm my suspicion. You don't have a switch where the switch ought to be, which means it's been monkeyed.

Now you have some real detective work to do!

That is EXACTLY how it looks with my far-sighted eyes . Sounds like someone installed a pressure switch, a no-no as they tend to fail with boosted brake pressure.

Check the front cross member, its back face. That is the disc/drum brake pressure proportioning valve block location and most logical place to install a pressure switch. If not there, trace the brake lines, it will be on that.

 

[edman]

Okay. I found a pressure switch in the brake line tucked up under the frame in a hard to see area. Previous owner must have put it there to keep it out of the elements. I pulled the wires off of it and re-installed the proper switch back on the pedal. Everything is good now.