goldgun

Hey guys
i have a 99 C2,i never hear the fan on the rear lid go on,i have a 03 C4S and i hear and feel it go on and off from time to time,on the 99 i tried letting it run idle for 15 minutes till the needle on the temp gauge almost covered the zero,thats the hottest the car gets at anytime,i heard the front fans but the rear fan never went on,any ideas what to check or do,i see somone had a similar post on this,Thanks in advance for any info

Loren

Normal.

Switch-on conditions for engine compartment fan (this fan pulls air into the engine compartment) The engine compartment fan is switched on when the engine compartment temperature is > 176 degrees F or the coolant temperature is > 216 degrees F.
If the ignition is switched off and the engine compartment temperature is more than 140 degrees F, the DME control module remains in readiness for another 20 minutes. During this time, the engine compartment temperature is retrieved every 10 seconds. If the engine compartment temperature is > 185 degrees F, the engine compartment fan is switched on for 20 seconds. If the engine compartment temperature is still > 185 degrees F after this time, the fan remains on for a further 30 seconds.

goldgun

Thanks Loren but i never heard it go on when i let it idle and get good and hot?

9 lives

ditto....I've never seen nor heard mine go on before. Any way to activate the fans to see if they are still even any good ?

Torontoworker

I checked mine after installing a fixed wing and started feeling paranoid that the fan wasn't working, so...

You can test it by removing the sensor that is pushed into a little rubber gromet located between the passenger side intake runners. Just look for the plastic covered wire that runs to this area. It's easy to remove - it just slides in and out. Pull it over to a container of water you've heated up to just below boiling (I used my wifes kitchen dial unit and safety here - use gloves and have the container either held by someone else or secured in place so it won't tip over) and dip the the bottom half of the sensor in the water using tongs. Motor warm and switched off - dip the sensor. (Keep any loose items away from the fan above you!!) The fan should come on right away as long as the water is above the 185 degrees as noted by Loren. If it doesn't...

Use a meter and check to see if the fan circuit is open by pulling off the fan plug and testing across the two spades where the harness attached. You can go the 12v supply route (battery or charger) to test the fan as well if you don't have a meter.

I rarely have my engine fan come on - I think I've heard it twice - once after a hot weather highway drive and straight into my garage with a shut down (dumb) and the other time parking after coming off the track and not doing a cool down lap (even dumber).

Optical TDI

Mine has never come after the car has been turned off either - even after a summer time (hot day) DE. Of course I did the cool down lap and let it idle for a few minutes each session.

I was just going to start a thread on this and searched to find one was started recently.

Would there be some kind of light or indication of malfunction if it wasn't working properly?

Torontoworker

DME 5.2.2, 7.2 & 7.8 = No CELL but will record fault Code, P1157 or P1158 = Engine compartment temp sensor.

Engine purge fan diagnosis:

Check fuse B4
Check sensor
Check relay on panel#2 for failure
Check fan for short