brake light question - need wiring and/or locator

I've got what appears (from a quick search on Google) a common problem: '93 1500 Suburban, generally an unmolested truck, but as of (I don't know how long, i've only owned it a few weeks) some time I have no brake lights (turn signals work, running lights work, etc.). I'm guessing I have a fuse bad leading to the brake switch (or a bad switch). If someone can direct me to the location (or a diagram of) of the proper fuses, junctions to check & explain each of the 6 wires that connect to the brake pedal switch, I would be most appreciative. Thanks in advance.

Chris

Reply to
clunfler
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u may have lost the ELECTRICAL GROUND to THE BED ... Happens All the time

clunfler wrote:

Reply to
tom

i wish, but there's no response back at the leads to the tail lights when I use a test light. Are the brake lights run through a relay? And, is there a main fuse? I can't seem to find anything but a bunch of non-responsive wiring leading to the steering column....wouldn't I get a response leading to the signal switch if it were the switch that were killing the brake lights?

-c

tom wrote:

Reply to
clunfler

use the rear bumper as the ground connection to ur TEST LIGHT Brake lights are wired thru the Signal lights switch..

DO the 4 way lights work in the BACK ? The 4 ways uses the same wires as the brake lights . so if they Work then it is the BRAKE LIGHT switch or the signal light switch in the column

clunfler wrote:

Reply to
tom

If the turn signals work then the wiring is good from the switch all the way back, the brake, turn and four way are all on the same circuit. Power for the brake lights goes from brake light switch to turn signal switch, where the switch can break the circuit to left or right otherwise if the turn signal was on and you stepped on the brakes they wouldn't blink.. More then likely its a bad brake light switch, at $10 most places, its worth trying time wise, 10 minutes to change. I have seen the wire break at the switch, maybe 5 times in 20 years turning wrenches, its the only one that gets moved when the switch is activated.. Its a white wire from the brake light switch to the turn signal, and an orange wire feeding the brake light switch. . The brake lights are feed by the drk green(right rear) and yellow (left rear) wires coming from the turn signal switch. . Brake and hazard are on same fuse, and its ether good or bad, they dont sometimes let power through and sometimes not. There is no relay in the circuit. The other four wires on the brake light switch are to disengage the cruise control, and unlock the torque converter.

Whitelightning

Reply to
Whitelightning

Thanks for the good info. By all symptoms, it sounds like the column switch...but I got a replacement & plugged it in (not installed) & got no brake light response still....maybe it wasn't properly grounded?

So, the orange wire goes from the signal switch to the brake pedal switch & back via a white wire? And, when the pedal is engaged, this circuit is open? So, I should be getting + voltage on the orange wire at the switch?

Last question...kinda dumb(er), I know...should be brake lights work with the key on & key off both or only when 'on'.?

thanks

-c

Whitelightn> If the turn signals work then the wiring is good from the switch all the way

Reply to
clunfler

The orange wire does not go to the turn signal switch at all, just the white wire. Power is always on.. The completed circuit is made when the brake pedal is pushed, its open when the pedal is up. The orange wire is feed direct by fuse panel.. There is no ground on the turn signal switch.. It still sounds like a brake light switch to me. Especially if the four ways work.

Whitelightning

Reply to
Whitelightning

Thanks again. OK. I've been tinkering w/ the pedal switch out (loose), so maybe I'm reading the switch positions backwards. So, the 'at rest' position of the switch when it's sitting on a bench is actually the 'pedal down' position with the switch installed. Yes? I'm writing out of memory here, but if I recall, I wasn't getting power at all to the orange or white wires at the pedal switch in *any* position....so, maybe it's just I've lost the hot+ lead coming into the pedal switch....man, that'd be great! I mean, less hassle to fix, at least. It seems like if the turn signal switch were the culprit (which a lot of folks seem to think ought to be the case), it would be something that would be somewhat intermittant until it finally went fully bad...then again, I guess I may not notice if it were so.

So, if I have no + voltage on the orange wire leading to the pedal switch, then *that* is the problem, right? Where does this wire originate? The fuse box or ??

thanks

-c

Whitelightn> > -c

Reply to
clunfler

Well, i knew it was something simple. Turns out it was the 2nd fuse for the brake lights (which apparently feeds the rear brake abs memory, the brake lights, the hazard lights & the radio dimmer & may also go thru another fuse...). Two problems I had were 1. checking the brake pedal switch w/ it off the pedal...so I was mis-reading the on/off positions & taking the + coming in from other sources as the proper feed for the lights when if fact it was not & 2. very little documentation to work off of (finally tapped into the Mitchel system from the fleet service center at work & got the info I needed to know where to look). So be it. It was frustrating, but a happy ending in my opinion.

thanks for all your input.

-c

Reply to
clunfler

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