GRANDFURY Posted December 11, 2003 Report Share Posted December 11, 2003 I'm replacing my coolant temp sensor and my thermostat this weekend but is there any other sensor that tells the fan when to turn on? My fan wont turn on by itself and I have it hooked up so it is on all the time but want it back to normal. Thanx. 8) Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted December 11, 2003 Report Share Posted December 11, 2003 As far as I know.. the coolant temp sensor runs the secondary fan. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 I don't have a secondary fan. Should I? Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted December 11, 2003 Report Share Posted December 11, 2003 What year and model car? Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 1989 grand prix 2.8 auto air. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 It is an LE Quote Link to comment Share on other sites More sharing options...
supreme_style21 Posted December 11, 2003 Report Share Posted December 11, 2003 Hmmm.... trying to think if mine has one or two.. I'm not too familiar with them... someone will know. Chime in! Quote Link to comment Share on other sites More sharing options...
GrandPrix34 Posted December 11, 2003 Report Share Posted December 11, 2003 I'm replacing my coolant temp sensor and my thermostat this weekend but is there any other sensor that tells the fan when to turn on? My fan wont turn on by itself and I have it hooked up so it is on all the time but want it back to normal. Thanx. 8) sensors dont turn on fans, I DO... hmm i dont know but just thought that was funny Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted December 11, 2003 Report Share Posted December 11, 2003 Check your fan relay in the pass side electrical center before you do the other stuff. They can just go out and also melt from the wires underneath making poor contact. Jud Quote Link to comment Share on other sites More sharing options...
AWeb80 Posted December 11, 2003 Report Share Posted December 11, 2003 I have Both Fans on a manual switch........engine gets hot I turn the fans on while waiting in traffic. i love it in the summer Dave Heh heh, I have the secondary fan on a switch.......i like it that way. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 yeah I got mine hooked up too but I want it to work proper. So the fan relay where is that? The pass side electrical where is that? Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 By fan relay do you mean the fuse 'cause it is fine I have it ran through the fuse and it works so is there another relay? Also where is the coolant temp switch? Is it the same as the coolant temp sensor or is it different? Sorry for being a bother but I want to get all the parts so I can get this done on saturday. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 11, 2003 Author Report Share Posted December 11, 2003 I have a cheap little mutli tester is there any way to check the ECM with that? Quote Link to comment Share on other sites More sharing options...
quaddriver Posted December 11, 2003 Report Share Posted December 11, 2003 I'm replacing my coolant temp sensor and my thermostat this weekend but is there any other sensor that tells the fan when to turn on? My fan wont turn on by itself and I have it hooked up so it is on all the time but want it back to normal. Thanx. 8) The ECM will use ECT to turn on the fan, typically the 660's have but one fan, but I have seen dual fan setups where the second is triggered by the AC demand and both can be triggered by excessive temp. However I have found, that a 660 in a w body with AC rarely needs the fan in cooler weather - even then sitting, the natural convection around the radiator is pretty good. Quote Link to comment Share on other sites More sharing options...
Thabulldog Posted December 11, 2003 Report Share Posted December 11, 2003 The damn fans turn on wayyy too late, one of the things I really want the chip for. Ive seen cars that have fans turn on as soon as the car is a few degrees above temp. Some reason GM thought it would be smart to have the fans turn on at like 220. Quote Link to comment Share on other sites More sharing options...
quaddriver Posted December 12, 2003 Report Share Posted December 12, 2003 The damn fans turn on wayyy too late, one of the things I really want the chip for. Ive seen cars that have fans turn on as soon as the car is a few degrees above temp. Some reason GM thought it would be smart to have the fans turn on at like 220. well, put your car on a scan tool, it will list what the ECM thinks the ECT is saying (and lists it as degrees) and will also tell you if cooling fan is requested and if ac demand is on....thats the easiest way to see if it is bad, and you can use an infrared thermo to grade the effort of the ECT by shooting the water outlet neck.... Quote Link to comment Share on other sites More sharing options...
Thabulldog Posted December 12, 2003 Report Share Posted December 12, 2003 My CTS is new, I figured it was just normal because it turns on around 220 consistantly. Maybe one day down the road I'll look further into it, thanks for the idea, Quad! Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted December 12, 2003 Report Share Posted December 12, 2003 If you have found the fuse you’ve found the relay. It’s the second little black box about 1’’ sq. Pull it and look for any evidence of heat, if so pull the whole box and check for burned wires underneath on that relay. The first relay (if you’re a/c works than that relay is good) is the same so you can swap them back and forth. Put the fan relay in the a/c and see if the a/c works. You can also ground the green/white wire from underneath the box that runs to that relay and the fan should come on with the key on. That’s the fan request wire from the ecm which gets it signal from the coolant sensor. Coolant sensor is under the throttle body. Take your air intake off and it should be easily accessible. To test the wiring-yellow is 5v, black is almost 0 ohms with the key on. Coolant sensor test about 3,400 ohms @ 100 degrees and about 185 ohms @ 212. Boil it. Temp gauge sensor is on the back of the rear head under the egr. It sticks out at an angle. As far as testing the ecm without a scan tool you can with a v meter and a pot. That’s a little more involved. See how far you get. If the relay and fuse are good and it still doesn’t work its your sensor or a broken wire from the ecm. I doubt it’s the ecm. Hope this helps. Jud Quote Link to comment Share on other sites More sharing options...
Lee Posted December 13, 2003 Report Share Posted December 13, 2003 There are two coolant tmp. sensors. The one for the dash is behind the motor on the driverside, next to the egr valve. It has a pigtail wire permanantly attached. The one to the ecm...to turn the fans off and on, is just below the throttlebody and forward a bit. Down behind the themostat housing...area. It is horizontal and screws in facing the front of the car. It has a wiring plug in right on it...no pigtail. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 13, 2003 Author Report Share Posted December 13, 2003 I got my fan hooked up like that now but I just ran a wire from the #86 terminal to a ground and the fan turns on with the ing. on had it like that all summer. Wat do you mean by pigtail? I hope I didn't get the wrong one I didn't want the one for the dash so I hope they didn't give me that one. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 13, 2003 Author Report Share Posted December 13, 2003 Thanx SLEEPER that was alot of info and it helped answer a bunch of Questions and now that I look at the new sensor I got it has a yellow and black wire so I got the right one. Thanx again man! 8) Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 13, 2003 Author Report Share Posted December 13, 2003 Well the new sensor is in and the fan still wont turn on. Quote Link to comment Share on other sites More sharing options...
GRANDFURY Posted December 13, 2003 Author Report Share Posted December 13, 2003 Could a bad thermostat cause this? If was stuck closed would the temp sensor still know to turn the fan on? Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted December 14, 2003 Report Share Posted December 14, 2003 AAAAbsolutely, If its a good sensor. The water hits the sensor before the thermostat. You still having trouble? Jud Quote Link to comment Share on other sites More sharing options...
topless94style Posted December 14, 2003 Report Share Posted December 14, 2003 Quick question, i remember seeing someplace there was a link on how to wire your fans up to switches. Can someone send me that link. Quote Link to comment Share on other sites More sharing options...
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