Hey guys. In the past year i have fitted a full NF dash, loom, heaterbox ect.. into my EB V8. Just the other night i noticed that when my heater is on the thermos come on and cool the engine to way below where it should be?

Has this ever happened to anyone before?

Just to throw a spanner in the works, all the parts i used come from different cars but i had both wiring diagrams and made sure everything would be where it should.
Here is a list of the parts i used.

EL V8 opt20; ecu, engine bay loom.
NF I6 GHIA; body loom, bem, climate control.

any ideas?

any help appreciated!

Just one more thing....yes i make sure the AC is turned off too.

How many relays do you have in your thermo fan relay pack that is fitted to your EL V8 ECU and loom? Please say you have three.

cooling fans come on when the climate control temp is set to low tems or hight temps, im afraid its normal mode of operation

tryed it in mine fans come on when heater set to 32*c but if you turn your AC off and run it in manual instead of auto fans shouldnt come on.

banarcus- will check today, why do you hope i only have three? WIll my car explode if there is a fourth...lol

Voids- ok will try it full manual, hopefully my electrical system is ok and its a normal operation.

Thanks guys!

Out of curiosity, do the thermos come on :

a) When you have the aircon turned on?

b) When you have the cabin fan turned up on full high?

Or do they switch off in these situations.

a) ac not on

b) yes fan on hi

Dont switch off, watched it til temp dropped to 78 C. fans were still humming strong. I think on full speed too.

When using a low series ECU with high series dash/climate control stuff, some of the signals between the climate and the ECU are reversed.

For instance, as in when the AC is on, non climate cars switch to ground but climate cars switch to +12v. So you need to have the compatible ECU to match otherwise you may get some strange results.

Without digging through the manuls to find out exactly what is different (there are 2 differences from memory) it might be something like that.

^^^^^^Blower Fan speed voltage to the ECU is another one IIRC with the above - I have modded a fan speed controller to correct this, but I can't say I've noticed any major change in thermofan behaviour during testing. I found engine coolant temp to be the bigger factor. Although obviously there are other variables.
Did you get the temp off the cluster in diagnostic mode ??
I'd say what he is getting at is the NF(EF) loom runs a 4 relay setup(with 4 lines to the ECU), whilst the NL's(EL) run a 3 relay setup(with 2 lines to the ECU). If you don't have this wiring sorted, then it could cause an issue.
What I'd suggest you do:
- clean the coolant temp plug and sensor, possibly also the sensor head that stays in coolant. Disconnect the plug, and turn ignition on, fans should run at full speed.
- Do the thermo fan EEC test as per the tech doco(with gear select, etc).
- Pull any fault codes on the ECU, the fan relays have a code each.
- Optionally, you can hook up fixed resistors to the coolant temp plug, to represent different temps (10 cents each from d**k smith, etc), so you can test if it's an input issue other than temp.
The V8's without CC have also another input to the ECU, recirculation overide - it's another 12v-0v one. I'm not sure if the V8 CC ECU's still have it, and it simply comes up with a code because it's not connected.

The only thing that doesn't add up to me is if you didn't have those issues with wiring sorted 12 months ago, why is it acting up now ??

^ i just notice dit now. Doesnt help that the car has done a whole 500kms in one year!

Arm- i might try my ecu in my mates DL and see what happens.

snap- yes the temp is off the cluster.

oh oh...i used EL dash loom, EL eng loom and EL LHS eng loom. Think i only used NF loom on the RHS on eng but cant remember??? This could be where the problem lies....

But today i had another try.

Turned car on from cold. Fans not on, turned heater on fans come on. Turned heater off. Wathced temp to see if and when fans come on. Before they came on i tried heater again......they didnt come on? Turned heater off. Then fans came on low at approx 78 degrees. Stayed on til temp got to 75 ish.. Tried heater again and they didnt come on...WTF?