volvo cooling fan, not sure if mine is working

i recently picked up a 96 volvo 850 turbo wagon. the previous owner said that before he did a head swap (bent valve from previous timing belt break) the cooling fan didnt run on its own and he had put in his own aftermarket temp sensor in the radiator (push through the fins style). he said after the head swap the fans started coming on like they should, he guessed that the (used) new head had a good temp sensor and that's why the fans worked now and didnt before with the old head.

anyways i personally have yet to see the fan turn on, i have grounded the fan relay and it will make the fan turn on high and low like it should and my ultra gauge shows that the coolant temp sensor seems to be reading fine.

while driving the coolant temp stays between 185-190, i have seen it get up to 215 while idling in my driveway and the fan had still not come on yet. I know some cars dont turn the fan on until north of 220 but i start getting worried at anything past that.

so does anyone know what temp the ECM turns the fan on at? is it above 215? i have 2 fan relays that i have tried so i dont think its an issue with that. maybe try a new temp sensor?

I really just want the reassurance that the fan will work when its suppose to by itself so i dont have to worry about it

Does it come on with the A/C compressor? If it doesn't. there is probably a problem in the control circuit for the relay, or the relay itself.

Fan temp sensor is a common failure point on P80 cars. It's mounted to the bottom of the thermostat housing and cheap aftermarket units tend to fail pretty quickly. I'd start there before going too crazy.

In reply to Streetwiseguy:

a/c doesnt currently work right now, a/c comp. clutch doesnt try to click on so it maybe a bad pressure switch or some other issue. i assume since it doesnt try to run the a/c it doesnt tell the fan to turn on, with the a/c switch on the fan stays off.

In reply to SlickDizzy:

i just dont see how it can be a bad sensor but still read like it should (from what my ultra gauge shows). i guess for $35 it doesnt hurt to try a new one

well after some looking around i found one person say the fan comes on at 216 and another person say 225 (could be low and high speeds). so i guess i can just let it get nice and hot and keep an eye on the temp gauge and see if the fan kicks on. thanks for the help guys