Ok guys I have a question. I have a 1986 Chevy K10 and I'm having a bit of electrical trouble. I took the gauge cluster apart recently (had a few bad bulbs) and the parking brake light bulb was missing. I installed one and the light stayed on regardless of if the e brake pedal was mashed in or not. What could be causing this?
Two switches ground the BRAKE warning lamp circuit causing it to light.
- The E-Brake pedal switch has failed with the contacts shorted or the pedal isn't returning far enough up to open the switch.
- The combination (proportioning and metering) valve switch has failed with the contacts shorted or the brakes had a leak and the valve was never re-centered.
- The wire(s) from the Combination valve or the E-Brake pedal or both is shorted to ground.
Unplug them one at a time to isolate the problem. If the lamp stays lit no matter which switch is unplugged you have a shorted wire.
And also (thinking bad ground somewhere) when the wipers are going the dash lights dim and brighten. What could be causing this? Thanks in advance for any input.
You are correct. That sounds like a ground issue.
Make sure the ground buss bar above the E-Brake pedal is tightly bolted down and any ground wire(s) are making good contact. Do a voltage drop test to somewhere in the cab.
Make sure the ground strap from the RH cylinder head to the cab is intact and making good contact.
Make sure the ground cable connection on the alternator bracket is tight and making good contact to the block and battery.
I usually go overboard on ground straps. Tying the whole body and frame together eliminates RF noise on my CB and cuts down on galvanic corrosion.
Grounds from the frame rails to the block using the motor mount bolts. Stock is one side frame to block.
Grounds from both Cylinder heads to the cab. Stock is only the RH head.
Both Frame rails to the bed. Stock is one.
Rad support to both frame rails. Stock is none.
Rad support to outer fenders inside structure. Stock is none.
Outer fenders inside structure to inner fenders. Stock is none.
One outer fender inside structure to the hood. Stock is none.
Both doors to the cab. Stock is none.
The positive side of things might cause this too... The three connections from the battery to the starter to the J-stud on the firewall and one more at the alternator and the J-Stud. Voltage drop tests will isolate where you're loosing volts.
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