About Steve Forbes Expertise Most car repair question
Experience ASE Master tech, Toptech in dealership, EPA cert.
State Police inspector, Shop Owner for the last 7 yrs and father to a son and daughter and husband to my highschool sweetheart
Roy wrote at 2006-07-02 23:42:44
Thank God for this answer and His guidance in leading me to this web page. My hanes manual says that the fan relay is in the powertrain control module (PCM). With this in mind and suspecting that they were expensive little suckers I proceeded to check the fan motors which were ok then just replaced the temp sensor. When this didn't work off came the PCM ready to be replaced. Somehow this didn't seem correct so I wen't looking further (here). Moral of this story: don't believe everything in them hanes books. Even if they had ment PDC, power distribution center, that still wasn't correct cause I looked in there too.
JPB wrote at 2006-07-12 23:40:37
Here is how to test (based on my 99 Dodge Caravan). Disconnect the coolant sensor plug. Does radiator fan run? If yes, problem is probably coolant sensor. If no, disconnect the Fan relay plug too. Test for Bat. 12.5 volt B+ to Gnd. Test for signal from PCM (Light Gr wire on my car). Is voltage to Gnd (Blk wire at opposite end from Bat,) around 0.1 volt? If not, your relay is not getting signal to turn on fan. If you connect Bat. to Drk Gn (fan motor), does fan run? If yes, and you have no signal from the PCM, then problem is probably elsewhere (e.g., PCM, wiring, etc). If there is a signal, and fan runs when tested above, then relay is suspect.
