So I've jumped the thermal switch on the thermostat housing, no power to the fan. Ive swapped the relays around under the hood fuse block, Not sure how to test the relays with a volt/ohm meter. Any help is greatly appreciated. TIA 🍻

 

Unplug the cooling fan connector and connect a wire to each of the two prongs in the plug and touch the wires to the battery. If the fan doesn't come on... the fan motor is bad. If it does, then you need to work backwards and you may need to test the relay. The A/C relay is the same... so if your A/C system works, you could swap the relays and see if that solves your problem. If you get the same result as you did before your post... it is likely that both relays are OK.

 

The fan is good if I straight wire it. As originally previously stated, There is no power to the fan. The therm switch is jumped, no power to the fan. I swapped the relays around, no power to the fan.

 

Fan fuse.

 

All engine compartment fuses good

 

I forgot to mention that recently did a head gasket and the radiator fan hasn't worked since.

So here's what I just noticed, that while the jumper is in the therm switch connector, if I ground the jumper while in the connector, the relay clicks and the fan comes on. Is there a ground somewhere that I missed when I reinstalled the head? Where does the therm switch get its ground? Car runs fine otherwise.

TIA

 

The ground for the fan switch is part of the ground bundle that bolts to the top of the thermostat housing. There are two wires in the fan switch... a green and a black wire. The black wire should be grounded full time and the green wire goes to the fan relay in the under-hood fuse box. If you ground the jumper and the fan comes on, then the black ground wire isn't grounded.

 

Foooouuuuund it!....lol.. thanks y'all 🍻

 

No problem. Glad you found the issue and know what needs to be fixed.