Thermo Fan Problems

mrwinky · 22-07-2007, 05:48 PM

I have a AU series 1 forte 4L, whose thermo fans aren’t running, I've tested the fans and they both work, I've tested the relays and they all work, all 3 of them, the fuses are ok, I tricked the computer into thinking it was running very hot (took sensor off back of the motor and placed cable across joints and nothing happened other than gauge reaching hot and warning sound going off, all the wires and that look ok, and neutral works fine on the 4 pin connector. But I get no volts from the others going to neutral. If I short over all the relays with a piece of wire only 1 fan works the one closest to the relays, drivers side, the other fan doesn’t come on, I'm guessing there is some sort of switch controlling the path somewhere else but don’t know where, is there a wiring diagram around for this? I check the wiring diagrams on the site but couldn’t see it there any ideas?

Any help much appreciated.

Jono

**Mechan1k** · 23-07-2007, 11:35 AM

Sounds like you have tested this extensively as well ... the only think i can think of is the connection back to the PCM for this.

Have you tried with another set of thermos????

How did your current fans???? did you use the connector to the loom ... or the put power to the fan motors direct???

FGII-XR6 · 23-07-2007, 12:54 PM

check to see it there is power on the coil of the relays and the input of the relays. if there is the fault is in the wiring from the relays to the thermos. if the power is missing from the coil the fault is either the wiring from the ECU or the ECU itself if you jump a wire from the battery to the coil the fan should run in this situation. if there is no power on the input contact of the relay the fault is the between the fans and the fuse box

mrwinky · 23-07-2007, 05:35 PM

Quote:

Originally Posted by Mechan1k

Sounds like you have tested this extensively as well ... the only think i can think of is the connection back to the PCM for this.

Have you tried with another set of thermos????

How did your current fans???? did you use the connector to the loom ... or the put power to the fan motors direct???

Ill have a look at the PCM connection, no i havent tried another set of thermos, i connected the fans straight from the battery didnt think to try from the loom, dont have a wiring diagram so i dont know if ill have the right cable before putting 12v down it. Where is the PCM located and whats the easiest way to get to it?

And Au3xr6, i shorted over the relays and only 1 fan worked, there is power on all sides of the relays, fan 1 to 3, shorting fan 1 turns on only 1 fan(drivers side), shorting fan 2 and 3 dont do anything which made me believe that either a cable is stuffed or the computer hasnt closed the switches for it to work... so to try and trick the computer into working i tripped the temp sensor on the rear of the block to read hot which still didnt work, and one question what does the sensor on the coolant control?, i shorted it out to test as well but nothing happened, no warning alarms or anything when shorted or disconnected.

**Mechan1k** · 23-07-2007, 05:40 PM

I have actually got my ute hot (even with all fans on high speed) ... and the warning light doesn't come on until the needle hits the red zone ... in other words ... WAY TOO HOT ... that's about 118 deg C.

PCM is in the passenger footwell ... behind the kick panel.

I actually had my auto elec guy re-wiring my thermos to turn on high-speed as soon as I turn A/C on Fan speed 1 ... works very well in Summer now. They had a decent wiring diagram for the fans and relays and connection back to the PCM ... but it went over a couple of pages in their book though ... quite details ... just a lot of tracing. Not sure on the pins that it uses though.

In the end though ... if you need new thermos ... www.ozeparts.com.au has then aroud the $134 mark from memory ... pretty cheap. I think Darren at FTG has them for $100 if he has any left.

mrwinky · 23-07-2007, 06:20 PM

do you know which book it came out off?

**Mechan1k** · 23-07-2007, 06:22 PM

It looked like a workshop manual with all sorts of wiring diagrams in it ... all the diagrams were large fold out pages though.

mrwinky · 24-07-2007, 07:59 AM

Any one know what the sensor on the coolant container, driver side, egg crate looking thing?

**Mechan1k** · 24-07-2007, 08:47 AM

That sensor on the header tank is for coolant level.