94 k1500 brake light fuse and the yellow wire going to the brake switch is getting hot. Any help is appreciated

[Dr13]

Out of no where the brake lights stopped coming on when the pedal is pressed. Brake light and turn signal switch are good. All other lights and indicators work. Now the lights come on, but the fuse and yellow wire connected to the brake light switch and the fuse are getting hot as soon as the pedal is pressed. Anyone able to help me out?

 

[Caman96]

You sure it’s not a white wire going to brake light switch?

 

[Dr13]

You sure it’s not a white wire going to brake light switch?

Positive, it's yellow

 

[Caman96]

Positive, it's yellow

That’s odd, never heard of a yellow wire, I’ve only seen white for these trucks. Never seen a fuse either, any chance someone d*cked with it?

You must be registered for see images attach

 

[Dr13]

That’s odd, never heard of a yellow wire, I’ve only seen white for these trucks. Never seen a fuse either, any chance someone d*cked with it?

You must be registered for see images attach

everything looks factory to me. There is a orange, yellow, pink and two purple connected together.

 

[AK49BWL]

Yes it's yellow for the brake lights circuit on the 94s. It's white after the multifunction switch. You'll need to check for breaks in your wires, possibly at the tail lights, or a bad connection if you have a trailer extension harness. Check the ground for the tail lights as well, bad grounding can also cause higher current draw.

 

[Erik the Awful]

bad grounding can also cause higher current draw.

More resistance = less current. Your current flow through the ground will never be more than when the ground is making its best connection.

Is there a short that's drawing more current through the wire? Is one of the bulbs a 24v bulb?

 

[Dr13]

Update, the yellow wire coming out of the switch is connected to 4 other yellow wires, all tied into one connector. Can anyone tell what each of those 4 wires goes to? Reason being one of those 4 wires is the short. If I leave the one that goes towards the engine bay off, everything works fine. Thanks

 

[AK49BWL]

Four directions: Center stoplight (CHMSL), brake light relay (if equipped), cruise control module, and an extra for "aux use" like a trailer brake controller. So if the one going to the engine bay is the issue, then check the wiring to the cruise control module.

 

[Road Trip]

I pulled the following directly from the '94 FSM. There's good info in here:

You must be registered for see images attach

Interestingly, it actually says "YEL or WHT". The OP's photo shows a yellow wire that's in the correct (Pin B) cavity.

It definitely looks to go to Pin A7 in the PCM as well as the relay.

1) My first instinct would be to unplug the CHMSL relay and see if the symptoms clear. (Quick go/no-go.)

2) If not, then a careful visual inspection of all the yellow wires that are part of the fanout from that splice,
looking for a chafe to ground?

3) And if that visual inspection doesn't prove fruitful, you may be forced to temporarily disconnect the 4 wires
from the splice in order to find out which branch is causing the excess current draw? This should net you a
conclusive diagnosis and literally a path to follow.

Just some ideas off of the top of my head based upon the wiring diagram above.

EDIT: When you find the bad spot in the circuit, please consider taking a sharp photo and
posting it so that others researching a similar problem will have an idea of what to look for.
Thanks in advance.

Hope this helps --