How crap are these things?

When I bought this car the fan switch was cracked and disconnected. I bought a new switch and connector, fitted them and assumed I'd fixed the problem. The fan worked when the switch wire was grounded, meaning the fan itself, relay and wiring all worked. However when connected the fan did not kick in and the car overheated. I cut off the connector at the roadside and grounded the wire. The fan kicked in and I drove home with the temperature stable.

I ordered and installed another fan switch (an Airtex Wells one). I ran the car up to temperature... and the bloody fan still didn't in!

I've checked the ground, and there's continuity between the fan switch body and the engine block/to ground, so I'm guessing there's no problem there. The connector is new. So I can only think the fan switch is the weak link.

Are they usually this shoddy or have I just been unlucky? The car had AC, which the previous owner removed. It's a single fan setup. Would the absence of the AC gear have any impact, even though a grounded wire still activates the fan?

Any advice or tips welcome. For now, I'm just going to wire it to ground. Not ideal, but I'm not changing another fan switch until I've pursued all other avenues!

 

If it works when you send the switch wire to ground... then it has to be the switch or the connector. Also, don't trust your dash gauge when diagnosing cooling problems. Get a cheap non-contact thermometer or find some other means to get an accurate temp reading.

 

That's a good idea about double-checking the gauge in the binnacle. I do have an infra-red thermometer that I could use to check the engine temperature. Where's the best place to actually aim it? The neck of the thermostat?

I've been reading about and I have heard that aftermarket fan switches and connectors can be dodgy. I might try to connect the fan switch and the connector using a piece of wire, to see if I can rule out the connector connection. Very annoying.

Fortunately I wired in a weatherpak connector, so should the fan switch fail on the move I can simply switch it to a pre-arranged ground at the road side. I guess I'd better check the connections in that too!