Fan Thermostat switch wiring?

[crspdsk8]

I am having difficulty getting my fan to operate off of the thermostat switch. I originally had it hooked up per the manual but it didn't come on so right now I have it wired directly to the battery so it is always on.

I want to get this figured out so I can get the body on.
Can anybody give me details on how to wire this up to operate off the switch correctly?

Thanks,
Charles

[BrentM]

Mine won't come on either, I ran a separate switch so I can turn it on. If you jump the wire going to the switch to ground it should go on at least then you would know if it was wired correct. I know a few others have had the same problem. I have not taken the switch out to test it yet since the radiator is full of coolant.

[britpit]

It's possible that the radiator is not grounded well to the chassis due to paint or powder coat. Also, any sealer that you put on the switch may be preventing good electrical conductivity. Additionally, the switch provided, at least on mine, was not robust enough to survive without a relay - although it did work a few times before crapping out.

I installed this item set from Derale which has worked well and can take the amperage:

D16737 Replacement Thread-In Probe for Derale Single-Stage Thermostat Fan Control
D16728 Replacement Thermostat for Derale Fan Controls - 180 Degrees

[crspdsk8]

Thanks for the responses guys.

I finally got the fan to operate off the thermostat switch! I installed my switch in the cylinder head to get a more accurate reading instead of the bottom of the radiator which I heard could run 30-40 degrees cooler.

In the dash harness, I spliced in the orange fan wire to a brown switch feed wire. On the front harness, I plugged the blue fan power wire to the fans blue wire. I split the ground wire coming off the front harness and ran a connecter to the fan ground wire and the other to ground the radiator/grill. And now it works!

I have driven it a few times and the it seems to be operating correctly. Time will tell if it decides to crap out. I am thinking of running a switch also so if the thermostat switch does take a crap, I can still get my fan on. I just don't know the best way to do this yet. I should be able to figure it out but any suggestions are appreciated!