Spals fan problem has me stumped
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,706
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From: Scottsdale Arizona
Spals fan problem has me stumped
I'm ready to pour gas on this thing and torch it to end my suffering. I'm not going to talk about the four weeks that I've been working on my brakes. I'm not going to complain about the multiple parts vendors that have totally screwed up my parts orders in that time, adding to my aggravation. I'm not going to rant about the slow brake fluid leak that took me a week and a dozen hours to solve. I'm going to talk about my Spal fans that kept me in my driveway this weekend. 
About when my brake marathon started, my Spals stopped working. I've checked the system from one end to the other. There is power to the relays, power to the plug at the base of the fans, they just won't run. I even took them off the car and tested them with a battery charger. They worked perfectly.
This isn't rocket science!
I'm at my wits end on this. Any suggestions before I drive it into the Bay?
About when my brake marathon started, my Spals stopped working. I've checked the system from one end to the other. There is power to the relays, power to the plug at the base of the fans, they just won't run. I even took them off the car and tested them with a battery charger. They worked perfectly.
This isn't rocket science!
I'm at my wits end on this. Any suggestions before I drive it into the Bay?
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,706
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From: Scottsdale Arizona
I've been using a wire to ground the sensors when the engine is cool. I think that the relays are tripping properly when the engine is hot, though that's harder to check. Still no fans.
Race Director
Joined: Jan 2000
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From: San Jose CA
What part of the area are you at? I can probably help out.
Safety Car
Joined: Oct 2000
Posts: 3,593
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From: Southern Indiana
So they work when you take them off the car?
And there is power right to the plug yet they don't spin?
its either the ground your using or they are hitting on something and stopping them from turning.
And there is power right to the plug yet they don't spin?
its either the ground your using or they are hitting on something and stopping them from turning.
Team Owner
Joined: Apr 1999
Posts: 21,953
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I'd be the wrong guy to call on the suicide hot line
But very early on my spal fans failed to come on and I and the vette boiled over. So I made the system simple. One came on with the ignition key and fan two got a manual switch
I think that I had a bad temp switch, but that did not matter since I was 30 miles from home and the quick fix from an auto parts store has worked flawlessly for about 4 -5 years
But very early on my spal fans failed to come on and I and the vette boiled over. So I made the system simple. One came on with the ignition key and fan two got a manual switch
I think that I had a bad temp switch, but that did not matter since I was 30 miles from home and the quick fix from an auto parts store has worked flawlessly for about 4 -5 years
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Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
Just to clarify, the fans do not come on when I jump the sensors. The relays do click though. I was doing this to test if power was getting to the plug at the base of the fans. I have it wired up with two different sensors. I don't imagine both would fail.
Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,706
Likes: 329
From: Scottsdale Arizona
Thread Starter
Race Director
Joined: Jul 2004
Posts: 12,706
Likes: 329
From: Scottsdale Arizona
There definitely is a single ground. It hasn't completely failed because my multimeter shows Voltage across the plug but I don't know how to assess if the ground is weak. That possibility did occur to me as both fans don't work and, other than the ground, the two systems are essentially separate.
Safety Car
Joined: Dec 2005
Posts: 4,270
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From: Central Michigan
There definitely is a single ground. It hasn't completely failed because my multimeter shows Voltage across the plug but I don't know how to assess if the ground is weak. That possibility did occur to me as both fans don't work and, other than the ground, the two systems are essentially separate.
but that's how I've always checked for a good ground
Race Director
Joined: Jan 2000
Posts: 12,399
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From: San Jose CA
There definitely is a single ground. It hasn't completely failed because my multimeter shows Voltage across the plug but I don't know how to assess if the ground is weak. That possibility did occur to me as both fans don't work and, other than the ground, the two systems are essentially separate.
If it's only grounding through the threads of a bolt, that may not be enough. If you're using a common ground that leads to an actual ground source, you may be overloading the wire leading back to the source.
Mine is grounded to the steering crossmember with a self-tapping screw.
What I'd recommend doing next is grounding the switch side of one of the relays to a known good ground, then run the ground of one or both fans to a known good ground. If they start working at this point, it would suggest either the switch is bad or the ground is bad.
Limping across the line
Joined: Oct 2002
Posts: 5,299
Likes: 109
From: Peoria Az
I agree If you have power all the way to the fans. and the relay is closing(= relay power and ground are good) then the ground you are using for the fans is bad.
By probing for voltage on your ground wire your test light or meter is provinding the ground for the circuit.
Run a separate ground lead for each fan to 2 different ground points on your frame
By probing for voltage on your ground wire your test light or meter is provinding the ground for the circuit.
Run a separate ground lead for each fan to 2 different ground points on your frame
Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
I ran a separate ground to the radiator support. I think there are bolts between the frame and the rad support but I suppose you never know. I'll try removing that connection and grounding directly to the frame to see if that solves the problem. I'll give this a shot tonight and let you all know.
Melting Slicks
Joined: Oct 2005
Posts: 2,056
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From: Redruth Cornwall
Hey Mike,
If all else tests OK, how about removing the relays and direct wiring through the sensor just to see if it/they kick in. Dont run it for long ...
Reason I suggest this is because the fans draw quite a load and sometimes the relay contacts get damaged by arcing when they open and close. Even though you may show the correct voltage at the plug, when the current draw kicks in it may be enough to stop it working.
Kind of similar to starters that appear to have the correct voltage but a poor ground causes high resistance etc etc
Always good to run a separate ground when installing hi amp accessories.
Thinking about it, if you connect your multimeter on the ohms scale across the relay outputs controlling the fan then apply power to the relay, see if the meter drops to 0 indicating relay is good.
I had a bad headlight relay on Pam's Ghia that was doing this....
Failing that, drop it off at the port and I'll pick it up at Southampton and sort it out for you....or you could fly me out as your personal electrician!
If all else tests OK, how about removing the relays and direct wiring through the sensor just to see if it/they kick in. Dont run it for long ...
Reason I suggest this is because the fans draw quite a load and sometimes the relay contacts get damaged by arcing when they open and close. Even though you may show the correct voltage at the plug, when the current draw kicks in it may be enough to stop it working.
Kind of similar to starters that appear to have the correct voltage but a poor ground causes high resistance etc etc
Always good to run a separate ground when installing hi amp accessories.
Thinking about it, if you connect your multimeter on the ohms scale across the relay outputs controlling the fan then apply power to the relay, see if the meter drops to 0 indicating relay is good.
I had a bad headlight relay on Pam's Ghia that was doing this....
Failing that, drop it off at the port and I'll pick it up at Southampton and sort it out for you....or you could fly me out as your personal electrician!
Last edited by jotto; Nov 14, 2011 at 02:14 PM.
Thread Starter
Race Director
Joined: Jul 2004
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From: Scottsdale Arizona
I don't mind sending the plane ticket, it's the cost of the inevitable drinking that concens me
