# 2008 Silverado overheating problem **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet, 1500\ **Created:** [March 25, 2020, 4:17am UTC](https://community.cartalk.com/t/2008-silverado-overheating-problem/161722 "2020-03-25T04:17:48Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![redneckred](https://avatars.discourse-cdn.com/v4/letter/r/50afbb/32.png) [@redneckred](https://community.cartalk.com/u/redneckred)\ **Post date:** [March 25, 2020, 4:17am UTC](https://community.cartalk.com/t/2008-silverado-overheating-problem/161722/1 "2020-03-25T04:17:48Z")
I have a 2008 Silverado 1500 work truck that has started to give me overheating issues. I have narrowed it down to the electric fans not kicking on unless the A/C is on. I know this is generally a relay issue, but a friend of mine told Me there is also a switch by the thermostat on the block. Is there such a creature or should I concentrate on the probable relay? I miss old fashion fan clutches. ---
**Author:** ![Bugmenot](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@Bugmenot](https://community.cartalk.com/u/Bugmenot)\ **Post date:** [March 25, 2020, 6:55am UTC](https://community.cartalk.com/t/2008-silverado-overheating-problem/161722/2 "2020-03-25T06:55:19Z")
I don’t know of any switch, and the electric schematics don’t show a switch. The three cooling fan relays are controlled by two ground circuits from the ECM. If both fans are working properly with the A/C, in both low and high speed modes, then the relays aren’t the problem. If both fans don’t run in low or if one or the other doesn’t run in high (with A/C), then there could be a problem with a fan, a relay, a fuse, or the wiring. Assuming both fans work as they should with the A/C but not at all based on engine temperature, the ECM may not be receiving a signal that the engine temp is high enough to trigger the fans. If that’s the case, the problem could be in the engine coolant temperature (ECT) sensor circuit. Could be a bad connection at the sensor, a bad wire, a bad sensor, or something wrong with the ECM ECT signals. Does the temp gauge in the dash seem to work okay? Is the CEL on? ---
**Author:** ![kurtwm1](https://avatars.discourse-cdn.com/v4/letter/k/13edae/32.png) [@kurtwm1](https://community.cartalk.com/u/kurtwm1)\ **Post date:** [March 26, 2020, 12:25am UTC](https://community.cartalk.com/t/2008-silverado-overheating-problem/161722/3 "2020-03-26T00:25:26Z")
$10 to replace the Coolant Temperature Sensor. ---
**Author:** ![redneckred](https://avatars.discourse-cdn.com/v4/letter/r/50afbb/32.png) [@redneckred](https://community.cartalk.com/u/redneckred)\ **Post date:** [March 26, 2020, 2:52am UTC](https://community.cartalk.com/t/2008-silverado-overheating-problem/161722/4 "2020-03-26T02:52:03Z")
The temp gauge work fine. That plus a light antifreeze smell brought my attention to the matter. There is no CEL at all.