Dsandine

I have been having a lot of trouble trying to figure out at what temp the electric fan is supposed to turn on, in the Haynes manual it says nothing, and the diagram they have is for a 1991 and that's it, but it is basically the same as my 93. I have been helping an issue with my roommates 1989 xj and the diagram I found for it, (you will see in first pic) says radiator temperature switch is supposed to close at 190 degree's. I trouble shot the whole system and everything works as should, turns out radiator temp switch is not closing at 190 degrees, and it is brand new autozone radiator that came with radiator temp switch already installed. I verified it is the switch that is not closing as coolant temp started to get over 210, analog guessing gauges suck but I would guess maybe it was like 215 or 220 and fan wouldn't turn on, I unplugged the temp switch and shorted the leads in connector together and fan kicked on, verifying everything else in that circuit is operational. But it also doesn't make sense for it to close at 190 as diagram says, as stock the 89 has a 195 thermostat and I heard running 210 is the norm so if the switch is supposed to close at 190 the electric fan would be running all the time as soon as vehicle warmed up. And then on my 1993 xj, which has the same wiring that is shown in Haynes manual gives me no idea of when the switch on thermostat will close or open or whatever it does to send signal to computer to energize the relay so my fan will get power. In zero degree temps the 1993 sits at 210 all day long, even if it was idling, now that we are in the twenties it goes a bit above 210 and will just sit there steady and fan will never turn on, also figured problem had to be with temp switch as when I unplugged temp switch from thermostat that some how told computer something was up which then energized the relay and my fan came on, I am also enclosing a pic of the wiring diagram for that circuit from 1991 to 1993 that I took out of Haynes manual, I couldn't find a pic online so I had to draw one, sorry its a mess but all the components are there. I'm not the most concerned now as it only goes a little bit above 210 (whatever temp that means if that gauge is even accurate) I am much more concerned about these two vehicles overheating when it starts getting warm again as I have heard the 4 liters (both xj's have the inline six) don't like to get too hot, and even through searching and Google and all that I could not find definite answers of when temp switches are supposed to close to allow fans to turn on.

http://i637.photobucket.com/albums/u...fan/relay2.jpg

http://i637.photobucket.com/albums/u...993number2.jpg

91familyxj

I belive my 91 kicks on around 190- 200. Im not 100% but right around there.

mike37

it should kick on at 215to220
sounds like you need a new sensor

but don't trust the stock guage to be all that accurate you my just be running at the right temp 210