gengine

So after running my '76 blazer last year all winter plowing snow, I borrowed the battery for my 84 k-15. Well, I was working for the last month across the state, and my wife was getting a lot of snow back home, and needed the plow. She's fairly handy, can change tires, does her own oil changes, usually doesn't need me for general maintenance type stuff. Well, she went and bought a battery, and hookedit up backwards. She heard a little pop and sizzle, but then nothing. So when I got back, I found the little "Pop and sizzle" and replaced the 30a fuse on the firewall where the noise came from. All the fuses in the panel are fine. They looked fine, still no start, and no lights, so I pulled them all again and tested them, just to be sure. Anyway, by playing around I found out that if I push the brake pedal, it starts right up. It stays running, and everything but the aftermarket radio work. I guess its not really a problem, but its still not right. By the way, the plow electrical was not hooked up at the time. So that eliminates anything there. I checked the trailer brake controller, and all seems fine there, and I changed the alternator with an extra, thinking the diodes in the voltage regulator might have fried, but that didn't help either. So, if you have any ideas where I can chase this down, I would love to hear them. Thanks!

gengine

I found a relay clear up under the dash plugged into a wire plug, so I pulled it out, and nothing changed. It started the same, and everything that I could think of testing worked the same way. Is this relay burnt out? Also, there is a light blue "cube" clear up under the dash also that is also hooked right into the wiring. What is it and could it be causing a problem?

MrChevy

You have to push on the brake pedal EVERY time you start it? That sounds like it is feeding the 12v from the brakes backwards to the switch so the switch will work.
Do the lights and everything work when you touch the pedal OR does it have to be running for everything to work (except the radio)?

It sounds like it is getting juice through the back instead of through the front like it is supposed to. OR Possibly it could be something like a neutral safety switch. I've seen a seatbelt switch do something like that, only nothing would work. I took a paperclip and bypassed it and the vehicle started right up. The repair shop owner had already replaced the solenoid, starter and neutral safety switch. I don't much care for repair shops that do that to customers, start replacing parts instead of finding the problem. The customer didn't need the new parts but he had to pay for them anyway. Not good business practice. I own an automotive machine shop, I shouldn't need to be telling a repair shop how to figure out problems.

Yours is going to be a process of elimination until you find it. Test light and VOM time.

Juice to the switch on the column BIG RED WIRE I think, with switch to start, juice to inside terminal on solenoid (big purple wire on starter)?

It is all pretty simple if you just lay it out in steps.

What switch is closing when you push the brake pedal BESIDES the brake light switch? Is the brake light switch a dual function switch.

Simple stuff to check. Step by step. DO NOT SKIP STEPS. LOL

You'll need the Boss out there to hold the switch in the start position to check some of those wires. Have your tester on a wire and have her touch the brake pedal. Do each wire until you find the problem.

arod23

I did the same exact thing ur wife did and it took me forevr to find the prob. but my guess its the fusible link on the firewall where the junction box is at. there should be one wire that splits into two and those are live wires.it "should" be a black round thing on it and it separates them into two.that should be ur fusiable link.also im including a lil info that i got from the "autozone" website that helped me out.

"In addition to circuit breakers and fuses, the wiring harness incorporates fusible links to protect the wiring. Links are used rather than a fuse, in wiring circuits that are not normally fused, such as the ignition circuit. Fusible links are color coded red in the charging and load circuits to match the color of the circuits they protect. Each link is four gauges smaller than the cable it protects, and is marked on the insulation with the gauge size because the insulation makes it appear heavier than it really is.

The engine compartment wiring harness has several fusible links. The same size wire with a special hypalon insulation must be used when replacing a fusible link."via autozone.com