chevylover5

iTrader: (1)

ok so before you ask, its not the usual problem! ok so i was driving around after having my car in stow all winter and i drove it all night and at the end of the night i shut it off to get some water ice. i come back and start it up and the fans dont kick on and i start to over heat. so i spend 35mins fighting with the hood, finally got it open and check the coolant i was fine and put the key on on the fans didnt come on. so i checked the fuse, thats fine, babied it home and the next day i look at the one relay on the rear wall and there is melted tape over it. so i take the tape off and i find a corroded bare wire jumping the two wires going into the relay. so i figure wtf were the people before me thinking. i bought it from a car lot, which ill never ever do again and i fight it thru all of its little "quarps" which i thought i had worked out by now and i find this crap UGH. so i change out the relay figuring it might have blown. nope. i checked the fans with a jumper, they both work. i replaced another relay for it, under the thermostat, nope. i check all the grounds i could find and they are all tight as can be. what else could it be?

OK so if i lost you heres a quick synopsis...
my fans wont kick on
the things i have checked and replaced or just weren't bad are...

-fans
-fuse
-relay on fire wall
-relay under thermostat
-fixed corroded jumper
-checked grounds

SO

What else could my problem be?

and

Why on gods green earth would they put a jumper, jumping the two wires on the relay that is on the fire wall?

chevylover5

iTrader: (1)

BUMP HELP ANYONE?????????????????????????????

DubyaSsixTA

Did you check the coolant temp switch on the passenger side head? Could be bad or simply a loose wire, which is my problem at the moment. Hope this helps.

naf

iTrader: (7)

The relay passes power to the fans when one of the smaller wires is grounded (the other smaller wire is provided 12 volts when ignition is on). Perhaps it was jumped to run constantly? The relay is grounded through the temp fan switch in the pass side head and/or through the A/C (pressure switch or some older models at the control head).

To diagnose, pull the lead off the temp switch and ground it with ignition on. If the fan runs the switch is either bad or not reaching sufficient temp.

Verify continuity between the switch lead and relay.
Verify 12 volts to relay (ignition on)
Verify constant 12 volts to relay (larger wire, usually from starter lug)
Verify 12 volts out to fans when relay fan switch wire is grounded.

In two fan set ups the primary fan is controlled as above, the secondary receives a signal from the ecm through another relay.

bobcex13

I have replaced and checked the switch on the side of the head and my fan still comes on @ about 240/250 if it comes on at all is there anotherswitch that I'm missing I have also changed the thermostat they ar both 166/175