Radiator Fan Won't Come On

[CB7 Fanatic]

I finished my mild tuck, and now the radiator fan won't come on. It took over a gallon of antifreeze, so I'm pretty sure it's full. I checked the ground, and it's good (same location as right corner light). Only other wire is the blue wire, which seems fine. What else could it be?

[noobcake]

is your car overheating?

[CB7 Fanatic]

is your car overheating?

It was about to. The needle was 3/4 of the way up.

[CB7 Fanatic]

The only thing I haven't connected back up is the blower...but I doubt it's connected. Also, my bumper lights aren't working. Still need to troubleshoot that.

[Losiracer2]

Its prob. the sensor that went bad. I think its called a thermoswitch or something like that. The one that screws into the coolant outlet pipe.

on H22's its on the T-stat housing.

[CB7 Fanatic]

it's not that. Just put in a Mugen one a few months back.

[wherm]

When I did my wire tuck I remember a couple of relays on the driver side. They were cylindrical, not square like typical relays. There were two of them, one for the radiator fan and one for the a/c fan. I had removed them thinking they were only part of the a/c system which I pulled out at the same time. Without those in there, the fan didn't work. I plugged them back in and the fan worked fine. Double check that you didn't pull those out.

Also, while I was troubleshooting, I learned that you can use a jumper wire to jump the wires on the thermo switch. If you jump these wires and the fan turns on, you're good unless the switch is bad. If you jump these wires and the fan does not work, check the relays I mentioned above and keep troubleshooting...

[CB7 Fanatic]

I did move those 2 relays. I'll have to check how they are grounded. If they are grounded by the bracket instead of a wire, I'll bet I don't have it grounded. I'll check that tomorrow after work.

If that doesn't work, I'll try the jumper. Thanks for the good info.

[CB7 Fanatic]

When I did my wire tuck I remember a couple of relays on the driver side. They were cylindrical, not square like typical relays. There were two of them, one for the radiator fan and one for the a/c fan.

I checked and both are for the A/C. One for the "compressor clutch", and one for the condenser fan.

[CB7 Fanatic]

Ok. Both fans turn on when I turn on the A/C. I'm at a loss. Not sure what to do.

[CB7 Fanatic]

Found my symptom in the service manual. Went through the tests and it failed at the cooling fan relay. Hopefully it's just coincidence that I did all this rewiring and this happened at the same time.

I saw a response on Wikipedia for this symptom that said it could be a bad temperature sending unit, but the service manual doesn't even mention it.

[XcluziveAZN]

you might have air in the system. Try bleed your coolant. That might solve the problem

[CB7 Fanatic]

you might have air in the system. Try bleed your coolant. That might solve the problem

It's taken 1.5 gallons already.

[wherm]

you might have air in the system. Try bleed your coolant. That might solve the problem

That's a good point. Especially since the bleeder is right by the thermostat switch isn't it?

[wherm]

It's taken 1.5 gallons already.

With the engine cold, and not running, open the bleeder screw and fill the radiator till a steady stream comes out the screw. Even though 1.5 gal are in there, it only takes a tiny air pocket to mess things up.