Killing me, electrical problem

Jsup

Jsup

Well-known member
Joined
Oct 31, 2008
Messages
812
OK, here's the thing, the second I turn on the key, I blow the fuse that support the cooling fans.

I checked the relays, the sensors, the fans themselves. All are working

Any suggestions?

Thanks
 
If a fuse blows instantly everytime, it is usually a short to ground.
That's where I would start to check the wiring.
 
Post a drawing of how it's wired. Is this a new install? Or has it been working and then started popping the fuse?
 
Disconnect the fan wiring at the fans. If the fuse pops the wiring to the fans after the relay had shorted to the chassis somewhere. If the fuse stays good, the fans are drawing more current than the fuse rating.
 
big_G said:
Disconnect the fan wiring at the fans. If the fuse pops the wiring to the fans after the relay had shorted to the chassis somewhere. If the fuse stays good, the fans are drawing more current than the fuse rating.
Click to expand...

Guys, I talked to John on this, it's the CONTROL SIDE of the relay that the fuse is blowing...the LO current side....he has a diagram/book set for his '91? C4, which has dual fans, apparently, where my '87 had just the one, plus a small pusher up front for a/c??

so it's not the main power side to the fans...believe it or not...

:clobbered:
 
Same logic applies. Pull the relay. If the fuse still blows, the power feed to the relay coil is shorted to ground.
 
big_G said:
Same logic applies. Pull the relay. If the fuse still blows, the power feed to the relay coil is shorted to ground.
Click to expand...

I pulled the relays. Both, and the fuse still blew. PLUS disconnected both fans. Still blew.
 
Jsup said:
big_G said:
Same logic applies. Pull the relay. If the fuse still blows, the power feed to the relay coil is shorted to ground.
Click to expand...

I pulled the relays. Both, and the fuse still blew. PLUS disconnected both fans. Still blew.
Click to expand...

Someone else is hanging on the line there, do you have a aftermarket stereo?? IF so, check around there first....

1/2 them installers are nutz....

:bonkers:
 
mrvette said:
Jsup said:
big_G said:
Same logic applies. Pull the relay. If the fuse still blows, the power feed to the relay coil is shorted to ground.
Click to expand...

I pulled the relays. Both, and the fuse still blew. PLUS disconnected both fans. Still blew.
Click to expand...

Someone else is hanging on the line there, do you have a aftermarket stereo?? IF so, check around there first....

1/2 them installers are nutz....

:bonkers:
Click to expand...
Nope

All stock.
 
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
 
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

Yet another reason I"m SO glad I drive/modded/wired my '72 myself, kept the thing down to a bare bones minimum on the electricals that keep the car running....none of that 'body control computer' etc type stuff.....

it works, simple as that....
 
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

There's a good start. Just unplug all those items, or as many as you can, and turn it on. If it still pops, it's a wire.
Start plugging things back in till it pops. Then it's that coil.
 
big2bird said:
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

There's a good start. Just unplug all those items, or as many as you can, and turn it on. If it still pops, it's a wire.
Start plugging things back in till it pops. Then it's that coil.
Click to expand...

Rather than keep banging fuses, why not get a 1156-7 bulb and wire it across the fuse terminal, the bulb will of course light, as the shorted wire will ground it.....then you go around unplugging loads/moving wires and watch the light....when you don't see the light, that's it....

I haven seen any light in a long time....:rofl:
 
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

I just cursed out loud
 
mrvette said:
big2bird said:
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

There's a good start. Just unplug all those items, or as many as you can, and turn it on. If it still pops, it's a wire.
Start plugging things back in till it pops. Then it's that coil.
Click to expand...

Rather than keep banging fuses, why not get a 1156-7 bulb and wire it across the fuse terminal, the bulb will of course light, as the shorted wire will ground it.....then you go around unplugging loads/moving wires and watch the light....when you don't see the light, that's it....

I haven seen any light in a long time....:rofl:
Click to expand...


Thanks Gene, will do good idea.
 
Jsup said:
mrvette said:
big2bird said:
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

There's a good start. Just unplug all those items, or as many as you can, and turn it on. If it still pops, it's a wire.
Start plugging things back in till it pops. Then it's that coil.
Click to expand...

Rather than keep banging fuses, why not get a 1156-7 bulb and wire it across the fuse terminal, the bulb will of course light, as the shorted wire will ground it.....then you go around unplugging loads/moving wires and watch the light....when you don't see the light, that's it....

I haven seen any light in a long time....:rofl:
Click to expand...


Thanks Gene, will do good idea.
Click to expand...

OK, now keep in mind that SOME drains for X amount of current draw will make the light glow to a varrying amount...but a dead short will make it really bright....so when pulling connections on loads...expect maybe a slight decrease in brill off the bulb....since all this is a unknown I"m trying to describe a phenomena ....not a very scientific thingy....sorry, best I can do with words....

:hissyfit::crutches:
 
mrvette said:
Jsup said:
mrvette said:
big2bird said:
big_G said:
Just for you, Jsup..:rolleyes: I checked my '91 shop manual. The gauges fuse, which powers the fan relay coil, also feeds many other circuits. A/C solenoid, stop lamps, daytime running lamps, both primary and secondary fans, 1-4 up-shift relay, alternator, air control valve, air divert valve, egr solenoid, and finally the canister purge solenoid. Welcome to my world. There is a pinched wire somewhere.
Click to expand...

There's a good start. Just unplug all those items, or as many as you can, and turn it on. If it still pops, it's a wire.
Start plugging things back in till it pops. Then it's that coil.
Click to expand...

Rather than keep banging fuses, why not get a 1156-7 bulb and wire it across the fuse terminal, the bulb will of course light, as the shorted wire will ground it.....then you go around unplugging loads/moving wires and watch the light....when you don't see the light, that's it....

I haven seen any light in a long time....:rofl:
Click to expand...


Thanks Gene, will do good idea.
Click to expand...

OK, now keep in mind that SOME drains for X amount of current draw will make the light glow to a varrying amount...but a dead short will make it really bright....so when pulling connections on loads...expect maybe a slight decrease in brill off the bulb....since all this is a unknown I"m trying to describe a phenomena ....not a very scientific thingy....sorry, best I can do with words....

:hissyfit::crutches:
Click to expand...

Did just what you said

Think I narrowed it down to a specific piece of real estate. I ran out of time today, I"m going back tomorrow.

Seems to be on the passenger side. Going under that side tomorrow.

CLoser. Thanks for the tip Gene. I don't care what they say about you.....you're OK!
 
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