Help wiring dual spals
Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Help wiring dual spals
I've had this dual spal setup in the C3 for about three years. Cools the stroker just GREAT! But there's a nagging issue that came up last summer and I am determined to fix now... Unless the AC is on, the fans will drop out, letting the engine get hot. Click the AC on and then of course they kick in and she cools just fine.
I got the schematic that I wired them with, on this forum but I dont' still have it. Here's what I can tell you without disassembling it all: There's three relays. One I marked AC so I know what that one does. There's one intake manifold sensor. I tried replacing that but got the same result
So the project for now is to rewire them and I need a schematic. Perhaps one relay instead of the three? It would be so simple to do that and I may just try it out. I don't know if one of my relays is bad or not; I just now swapped out the one that's NOT for the AC switching. I got the same results.
When I ground the sensor, the fans come on just fine. But after a minute or so they shut right back off.
Cannot afford an expensive controller but I can certainly wire up relays if I can get some ideas. HELP anyone? It kills me that these things worked fine for about two years before this started.
I got the schematic that I wired them with, on this forum but I dont' still have it. Here's what I can tell you without disassembling it all: There's three relays. One I marked AC so I know what that one does. There's one intake manifold sensor. I tried replacing that but got the same result
So the project for now is to rewire them and I need a schematic. Perhaps one relay instead of the three? It would be so simple to do that and I may just try it out. I don't know if one of my relays is bad or not; I just now swapped out the one that's NOT for the AC switching. I got the same results.
When I ground the sensor, the fans come on just fine. But after a minute or so they shut right back off.
Cannot afford an expensive controller but I can certainly wire up relays if I can get some ideas. HELP anyone? It kills me that these things worked fine for about two years before this started.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I would Google the Dual Spal fans certainly Spal has a schematic on their site for relay controls....
or go to Tom DeWitts site, certainly he would have something there, if not he can email it to you , I hope....
much faster to just d/load one than any possible description....
or go to Tom DeWitts site, certainly he would have something there, if not he can email it to you , I hope....
much faster to just d/load one than any possible description....
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
PM me your email. I have the wiring instructions and diagrams. You do need all 3 relays according to this. There is a specific way to wire them also that is different than I originally thought.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
there was a post some time ago concerning the voltage build-up when the relays open while the car is moving, causing the fans to "free wheel". they'll act like a generator and cause an arc that might damage the relays. it was suggested that a diode be placed across the relay contact to ground this voltage spike.
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
It sounds like you have the AC relay wired in SERIES with the Enable line [for the two fan relays] instead of PARALLEL.
I would suggest you remove the AC relay from the circuit completely and get the system working with the NON AC wiring diagram. Once that is running, just connect a wire from the output of the AC relay to the ENABLE pin of the fan relays.
I would suggest you remove the AC relay from the circuit completely and get the system working with the NON AC wiring diagram. Once that is running, just connect a wire from the output of the AC relay to the ENABLE pin of the fan relays.
I've had this dual spal setup in the C3 for about three years. Cools the stroker just GREAT! But there's a nagging issue that came up last summer and I am determined to fix now... Unless the AC is on, the fans will drop out, letting the engine get hot. Click the AC on and then of course they kick in and she cools just fine.
I got the schematic that I wired them with, on this forum but I dont' still have it. Here's what I can tell you without disassembling it all: There's three relays. One I marked AC so I know what that one does. There's one intake manifold sensor. I tried replacing that but got the same result
So the project for now is to rewire them and I need a schematic. Perhaps one relay instead of the three? It would be so simple to do that and I may just try it out. I don't know if one of my relays is bad or not; I just now swapped out the one that's NOT for the AC switching. I got the same results.
When I ground the sensor, the fans come on just fine. But after a minute or so they shut right back off.
Cannot afford an expensive controller but I can certainly wire up relays if I can get some ideas. HELP anyone? It kills me that these things worked fine for about two years before this started.
I got the schematic that I wired them with, on this forum but I dont' still have it. Here's what I can tell you without disassembling it all: There's three relays. One I marked AC so I know what that one does. There's one intake manifold sensor. I tried replacing that but got the same result
So the project for now is to rewire them and I need a schematic. Perhaps one relay instead of the three? It would be so simple to do that and I may just try it out. I don't know if one of my relays is bad or not; I just now swapped out the one that's NOT for the AC switching. I got the same results.
When I ground the sensor, the fans come on just fine. But after a minute or so they shut right back off.
Cannot afford an expensive controller but I can certainly wire up relays if I can get some ideas. HELP anyone? It kills me that these things worked fine for about two years before this started.
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Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
It sounds like you have the AC relay wired in SERIES with the Enable line [for the two fan relays] instead of PARALLEL.
I would suggest you remove the AC relay from the circuit completely and get the system working with the NON AC wiring diagram. Once that is running, just connect a wire from the output of the AC relay to the ENABLE pin of the fan relays.
I would suggest you remove the AC relay from the circuit completely and get the system working with the NON AC wiring diagram. Once that is running, just connect a wire from the output of the AC relay to the ENABLE pin of the fan relays.
Thread Starter
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
there was a post some time ago concerning the voltage build-up when the relays open while the car is moving, causing the fans to "free wheel". they'll act like a generator and cause an arc that might damage the relays. it was suggested that a diode be placed across the relay contact to ground this voltage spike.
The relays that came with the unit did indeed, show a diode in the diagram ... I was wondering why it was there. Thanks for that.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
I remember looking at the diagram that's on the side of the relays that came with the unit, yesterday when I was under the hood. I was comparing relays to swap them out for trial run.
The relays that came with the unit did indeed, show a diode in the diagram ... I was wondering why it was there. Thanks for that.
The relays that came with the unit did indeed, show a diode in the diagram ... I was wondering why it was there. Thanks for that.
as for the fans in free wheeling mode, I seriously doubt they ever generate more than 12 volts or so to be fed back into the system, have to be doing some serious MPH to do that....
the most likely thing is the fans of course draw almost no power from the car as the onrushing air relieves the fan loading, a free no load motor conditioin makes the motor draw maybe 1/2 a amp if that....