73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Electrical => Topic started by: jonny on January 17, 2016, 05:36:04 pm

Title: stumped/ complete power outage
Post by: jonny on January 17, 2016, 05:36:04 pm
I was working on my 87 the other day. Someone told me if I cleaned tracks an motors for pwr door windows they may start moving faster. So as I'm removing the panel, while truck is running and charging battery, I arched out between pins on window switch. The truck immediately shut off and now I have nothing. I just figured it was a fuse but I've checked them all twice and replaced relays. I have no interior, headlights or power to ignition at all. But when I pull (DM) fuse the door buzzer starts going off. So I know there is power around in there somewhere. I checked pwr to starter an it will spin starter but not engage when using screwdriver on lugs. I have torn most dash apart trying to look for an inline fuse or something aftermarket. But no luck. Anyone have any ideas.
Title: Re: stumped/ complete power outage
Post by: frotosride on January 17, 2016, 10:08:52 pm
Check the fuse on the firewall. It just looks like a flat piece of metal with two threaded post. This goes down to the solenoid for the starter and then into the cab for power.
Title: Re: stumped/ complete power outage
Post by: jonny on January 18, 2016, 07:32:01 am
on firewall in engine compartment, right? should I just jump post to post?
Title: Re: stumped/ complete power outage
Post by: bd on January 18, 2016, 09:36:56 am
The bar between the two posts is not a fuse.  It is merely a jumper to connect the two posts together.  Give the wires that attach to the two posts a tug to see if any stretch or separate.  Then go down to the starter and tug on the smaller gauge wires that attach to the 3/8" battery cable stud on the solenoid.  The wiring harness incorporates fusible links (ultra slow blow fuses) at the starter and firewall junction block.  If the fusible links stretch or separate, they are blown.
Title: Re: stumped/ complete power outage
Post by: jonny on January 18, 2016, 10:00:22 am
Tried jumping fusible links, but nothing. I'm heading into column next. Thanks for the tips. BD, your quote by Rich is spot on.
Title: Re: stumped/ complete power outage
Post by: jonny on January 20, 2016, 08:27:35 pm
still nothing, cleaned out garage so I could fit truck in for next few days while weather is supposed to be bad. Hope to find someone with another idea.
Title: Re: stumped/ complete power outage
Post by: bd on January 20, 2016, 11:42:21 pm
Do you have a test light?
Title: Re: stumped/ complete power outage
Post by: frotosride on January 21, 2016, 05:20:46 pm
The bar between the two posts is not a fuse.  It is merely a jumper to connect the two posts together.
 
Wow all this time I thought that was some stupidly designed open face fuse.. maybe I should read a little more careful when I look at these schematics
Title: Re: stumped/ complete power outage
Post by: Flytengineer on January 30, 2016, 07:25:53 am
I have an 87 K5 with a 350 TBI. The same thing happened to me while putting air in the tires at a service station during a trip a few weeks ago. After finishing with the air I tried to start the beast and saw a slight puff of smoke come from between the hood and cowling and then I had nothing. The only power I had was things that are NOT powered thru the ignition switch. After several hours of tracing and tearing the dash apart under the steering column I found a fusible link burned where it connected to the block mentioned earlier on the firewall. The fusible link visually looked fine.