Hey guys, I've got a problem with my thermofans, they seem to be intermittant, I first noticed this going up to my mates place the first time I got the Falcon on the road, its a steep hill climb on a dirt road, so you're only doing 40km/h or so, the thermofans won't kick on high speed, they are only on low, regardless of how hot the car gets.

It was getting close to overheating on the last stretch of the climb, sitting on the R in normal and raising more and the thermofans still wouldn't kick onto high.

Then we had a short in the wiring which blew the fuse, I replaced the fuse and reterminated the wires and put new connectors on them, they kicked in on idle, but they won't do it when the car gets hot again after driving it.

When you start the car with the A/C on, they go onto high, but won't when the car gets warm, only ever low.

This is what the temp guage was sitting on after going up to my mates place:





It doesn't play up on the freeway.

I've got all new radiator hoses, new genuine thermostat, new water pump, new coolant overflow bottle, radiator rodded and new tanks put on and fresh coolant, any idea on what would be causing this thermofan problem?

Where are the thermofan relays, I might replace both, and if that isn't the problem I'll replace the fans.

Not 100% sure on EL, but on EF, there are 4 relays (2 grey, 2 blue) in between the airbox and passenger headlight.

Anywhere in the 'normal' range is just that, "normal". Depends on what temp thermostat you run, how efficient your radiator is, even igniton timing, can affect the operating temp. As long as it's not on the "H", youre OK.
Fans are not required on the highway, there is enough air flow through the radiator, crawling along with A/C on with boot load of luggage and 5 people in car, will make the temp go up.

No problem on the highway, but in traffic it starts heating up quickly and that hill climb really gets the temp up, it will climb higher than R on normal towards the red zone if I go up the hill any slower.

I've lost high speed operation on the thermos even with A/C running.

My car is modified too I guess that could be adding to the problem, cammed, bigger exhaust valves, ported/polished, stiffer valve springs etc.

Anyone have any idea which is the high speed wire for the thermo? Is it the orange wire or the pink one?