What is the deal with my electric fan???

[soule64]

This thing is driving me nuts. I have gone through 3 temperature switches in the last month, which is actually 20 miles and about 45 minutes of running time since I am still in 'shakedown' mode after the rebuild. I got the fan and control/relay from Summit and so far they have replaced the temp switches for free. I wired it exactly per the schematic and have double-checked all of the connections. If I understand this thing right, the thermal switch is an open circuit (when cold<180deg) to ground for the relay. A bi-metallic strip or thermal compuond reacts to heat and closes the circuit at 180deg and the relay closes and connects the fan to the battery. So far so good? I installed the switches in the water jacket of the intake manifold just below the thermostat and used a small amount of teflon tape on the threads of the switch, but checked each installation for ground with a multimeter - all were good. They have all worked at first, for at least the first cycle, but die at some point after that. I have taken the lead each time and grounded it to the engine block and the fan comes on. Next, I have taken each of the bad probes and soaked the ends in boiling water - each time there is no continuity (there should be, right?). The last time I talked to Summit, the guy said that I must have too much voltage going through it...Huh? Next he tells me that I should bypass the temp switch and control it manually with a switch in the cab. I told him that I paid for a system that would run on it's own without me having to rely on me remembering to turn it on (I am going to add a manual switch in addition to the one in the manifold) and it should work as advertised. SO... probe number four is on it's way. Have I jacked this thing up or is there a possibility that I got 3 bad probes in a row? Thanks.

[chevy_mike]

Based on your diagram above, you should have everything wired correctly. About the only thing I would change is, your ground wire on the fan should be the same size as your input wire (in your case, 10 gauge) but that would not harm anything with the temp probe.

If this is a Summit brand kit, they are typically sourcing the lower quality items to keep the price point lower then other similar items. I know when I did this setup in my '69 Camaro, I used a Painless Wiring temp probe and did not have any issues.

The setup I am going to use in the '69 truck is a Spal controller, which makes the fan variable speed based on engine temp. Higher the temp, faster the fan run.

Wish I could offer better help but it looks correct. Good luck.

[markster5]

you might try checking countinuity from timp switch and battery groung when instaled on engine. possable bad manafold ground or switch to manafold!

[rlm316]

How many wires are on the temp probe? One wire means that the path to ground/resistance is completed upon the necessary condition being met. Two wires would either be a positive voltage switch with a return conductor or a milliamp/resistance signal. If you put positive voltage on a one wire switch it would burn the sending unit but probably not the relay. Hope this helps.

[soule64]

It only has a single wire to the temp switch. And like I said, if I take the wire off of the temp switch and ground it, the relay clicks and turns on the fan. But serioulsy, is it possible to get three bad switches in a row in less than a month???

[soule64]

Forgot to mention, when the last one failed I was stuck in traffic and the the temp started to creep into the red. I pulled over, pulled the wire off the switch and bit off the end and wrapped it around one of the steel brake lines off the master cylinder and drove home running it full time.

[rlm316]

Check the grounds from the block to the frame, the frame to the body and back to the battery. With the temp switch only pulling in the coil load, it should not have enough current on it to burn the contacts. It should also be sturdy enough to handle some over range stresses. I don't know where the country of origin is for the switch, but you may want to try either a GM switch or a name brand manufacturer for the next replacement. If the box the switch Summit is selling you says China, you may never get a good one.

[soule64]

The grounds are all new braided straps mounted to bare metal in the configuration that you mentioned. I got probe #4 installed installed but I don't trust it. I wired in a manual on switch just in case. I guess if this one goes out i'll try a different brand than the summit brand.

[russellmarling]

I also bought the summit relay kit and I am on my third thermoswitch. They are complete garbage. At least summit has been replacing them for free...

[chevygurly]

dang! I would be pissed off. I have used Zirgo fans on my projects. No problems yet. Here is a link for it http://www.thehoffmangroup.com/zirgo...ingfans&r=5010