Mike S. Posted January 23, 2007 Report Share Posted January 23, 2007 I own a 1994 Seville SLS, and my cooling fans aren't working right now. I first looked to the fuse, and it was fine. I tried locating the coolant temp sensor and the relays, and could find neither. It would be a great help if somebody could tell me where to find these. Are there any common fixes for the cooling fans? Thanks in advance. Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 24, 2007 Report Share Posted January 24, 2007 The cooling fans come on low speed when you turn on the air conditioner. If you start the engine, let it idle, and turn on the A/C, the fans should start. If not, check the A/C COMP fuse (10 A) in the engine compartment fuse/relay center, and the COOL FANS maxifuse (50 A) in the RH Maxifuse Block. If they are good, check Cooling Fan Relay #1. Have someone turn on the A/C and see if it is clicking. The cooling fan relays are on the radiator support below and between the cooling fans. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Mike S. Posted January 26, 2007 Author Report Share Posted January 26, 2007 Ok, so I determained that the fans still work by hooking running it to a battery. Where do I find this 50 amp maxifuse? If the coolant temp. sensor is the problem, how difficult is it to replace? Thanks. Link to comment Share on other sites More sharing options...
growe3 Posted January 26, 2007 Report Share Posted January 26, 2007 Why do you say the fans do not work? What is the engine temperature when you are checking the fans? The fans do not come on until about 220-225 degrees. To do a basic test, with the engine running turn on the AC, both fans should come on. Turn off the AC and both fans will shut off, unless the engine temperature is above 225 degrees. These engines normally run 200-225 degrees, they can handle much higher temperatures of course, but closer to the temps I noted are the normally what to expect. -George Drive'em like you own 'em. - ....................04 DTS............................ Link to comment Share on other sites More sharing options...
Mike S. Posted January 26, 2007 Author Report Share Posted January 26, 2007 I did the AC test a week ago, and they did not come on. I first noticed a problem with the engine heating up when stopped in traffic. Since the fans still come on when wired to a battery, am I to assume that it's the temp sensor? Link to comment Share on other sites More sharing options...
wings2fly Posted March 27, 2007 Report Share Posted March 27, 2007 I own a 1994 Seville SLS, and my cooling fans aren't working right now. I first looked to the fuse, and it was fine. I tried locating the coolant temp sensor and the relays, and could find neither. It would be a great help if somebody could tell me where to find these. Are there any common fixes for the cooling fans? Thanks in advance. Mike: Just went through the exact same issue on my 97 STS. Looks like you already know that the relays are good on the rad support.....right ! Okay you need to check the feed wires for both the high speed and low speed relays continuity back to your PCM . Chances the feed from the PCM to your relays is broken. In other words the PCM is commanding the fans to work but the signal can't get there!! You will need a wiring Schematic for your fan cooling circuits some you can identify which pin is you out put from your PCM. If you find the short all you need to do is cut the wire ( I know this sounds Scary)and run a new feed to the high speed side of the fan circuit. It works and it is way cool when you know that big chunk of aluminum up front is getting its life giving cooling air. Good Luck!!! Best regards to all you Cadillac Gentlemen and women out there, Daddyscaddy Link to comment Share on other sites More sharing options...
djt370 Posted January 13, 2009 Report Share Posted January 13, 2009 I own a 1994 Seville SLS, and my cooling fans aren't working right now. I first looked to the fuse, and it was fine. I tried locating the coolant temp sensor and the relays, and could find neither. It would be a great help if somebody could tell me where to find these. Are there any common fixes for the cooling fans? Thanks in advance. Mike: Just went through the exact same issue on my 97 STS. Looks like you already know that the relays are good on the rad support.....right ! Okay you need to check the feed wires for both the high speed and low speed relays continuity back to your PCM . Chances the feed from the PCM to your relays is broken. In other words the PCM is commanding the fans to work but the signal can't get there!! You will need a wiring Schematic for your fan cooling circuits some you can identify which pin is you out put from your PCM. If you find the short all you need to do is cut the wire ( I know this sounds Scary)and run a new feed to the high speed side of the fan circuit. It works and it is way cool when you know that big chunk of aluminum up front is getting its life giving cooling air. Good Luck!!! Best regards to all you Cadillac Gentlemen and women out there, Daddyscaddy Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 13, 2009 Report Share Posted January 13, 2009 The temp sensor also is used to drive the temperature gauge, so it that works then the engine temperature sensor is working. If it wasn't it would throw a code. In any case, it's in the rear cylinder head on the left (driver's) side. The schematics for most years has been scanned in and posted by BodybyFisher and others, but I don't turn it up in a search. The basic principle is that you have two relays, and the fans are in series for low speed, running on 6 Volts apiece, and both have 12 Volts on high speed. The fans come on low when the A/C is on, or the coolant temperature is above a comfortable level, and they come on high speed if the coolant temperature approaches 240 F. The simplest way to check them is to turn on the A/C and see if the fans are on low speed. If they aren't, then the first thing to do is to check the fuses and fans and you have done that; the next thing is to check the relays and wiring. If you need a schematic and someone doesn't pipe up with a link to an old post with it, I'll scan it in from my 1997 FSM and post it. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
TAHIR Posted January 14, 2009 Report Share Posted January 14, 2009 WHRER IS THE FUSE BLOCK FOPR THE COOLING RELAY SYSTEM? Link to comment Share on other sites More sharing options...
Cadillac Jim Posted January 14, 2009 Report Share Posted January 14, 2009 I believe that it's in the main fuse block above the steering column behind the air cleaner. -- Click Here for CaddyInfo page on "How To" Read Your OBD Codes-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data -- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC Yes, I was Jims_97_ETC before I changed cars. Link to comment Share on other sites More sharing options...
Number97 Posted February 5, 2009 Report Share Posted February 5, 2009 The temp sensor also is used to drive the temperature gauge, so it that works then the engine temperature sensor is working. If it wasn't it would throw a code. In any case, it's in the rear cylinder head on the left (driver's) side. The schematics for most years has been scanned in and posted by BodybyFisher and others, but I don't turn it up in a search. The basic principle is that you have two relays, and the fans are in series for low speed, running on 6 Volts apiece, and both have 12 Volts on high speed. The fans come on low when the A/C is on, or the coolant temperature is above a comfortable level, and they come on high speed if the coolant temperature approaches 240 F. The simplest way to check them is to turn on the A/C and see if the fans are on low speed. If they aren't, then the first thing to do is to check the fuses and fans and you have done that; the next thing is to check the relays and wiring. If you need a schematic and someone doesn't pipe up with a link to an old post with it, I'll scan it in from my 1997 FSM and post it. I think the previous post says that the fans come on low speed when the A/C is turned on; but the fans turn on high speed when I turn on the A/C in my '97 Deville. Which should it do? If the fans come on high speed when the A/C is turned on does that mean there is a problem? I have been having overheating problems and have come to the conclusion that it must be the radiator, (mostly because that is all there is left to repair). Link to comment Share on other sites More sharing options...
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