Thread: D2 Td5 electric fan always on

Originally Posted by Campaspe Man

Thanks Dave. In relation to the stuck relay idea, would the fact that I can force it off using the Hawk Eye suggest this isn't the cause? And if not, can a stuck relay be unstuck?

Cheers, Myles

Im pretty sure that your on the money if the hawk eye is shutting it off that its not a stuck relay but Id want to sit down and relook at the trace for the main feed to the fan relay just in case its using a second control relay. Some vehicles have multiple control paths that aren't immediatly apparant (one relay feeding another, one from say AC, one from an overheat control) off the top of my head Im cant say for certain that the TD5 electro mechanical control doesnt do the same thing.

Stuck relays can be unstuck but its usually only a temporary fix, relays are cheap enough to just replace if they are being an issue and usually you can swap them one for another and see if the fault follows the relay by causing a problem in another system.

I was going to post about the stuck relay, but then OP said he can control fan via Hawkeye.

I would try two things.

1. disconnect the coolant sensor plug

You say you have another D2? If so,
2. try the HVAC head unit from that other D2. Not hard to remove, just the tricky side lugs (credit card sized things help) couple of plugs.

Also, I can't recall where/how ... but there is a diagnostic process you can go through on the HVAC head unit. Press a few buttons in a magical way and so forth.

Strange thing, I remember I had this always on condenser fan on my D2a. I didn't diagnose it, thought it weird, and annoying as back then the battery was very weak, and I got caught a couple of times trying to start it with weak batt ... and problems that come with that. I just went away itself. I can't remember doing anything specific about it, and the only thing that may have come close to an accidental fix, was that one day I was sorting a leaking cooling system. Had to sand down the temp sender port as part of that fix up and I removed the temp sender connector to be sure no breakages there. I don't specifically recall that it stopped self running after that, may have before that too.
But it was annoying that when having ign on whilst I was sorting the D2a, having that fan on ... had to keep it on a charger too.

Originally Posted by AK83

Also, I can't recall where/how ... but there is a diagnostic process you can go through on the HVAC head unit. Press a few buttons in a magical way and so forth.

HVAC is not diagnosable with the Nano. Good point, Arthur.

Do this" Turn ign off; Hold down Auto and the air distribution buttons Keep holding them and turn key to ON; Wait for a few beeps to sound and let go. The display will show some codes. Got a list here somewhere.

Originally Posted by Tins

HVAC is not diagnosable with the Nano. Good point, Arthur.

Do this; Turn ign off; Hold down Auto and the air distribution buttons Keep holding them and turn key to ON; Wait for a few beeps to sound and let go. The display will show some codes. Got a list here somewhere.

00 = no fault
11 = in car temp sensor
12 = ambient temp sensor
13 = thermistor
14 = heater coolant temp
21 = left sunlight sensor
22 = right '''
31 = left temp servo motor
32 = right. '''
33 = distro servo motor.

Not sure if this helps. Maybe 14 or 13 could trigger the fan, but it's not an area I really understand.

Sorry forgot the bit about the Hawkeye cycling the fan off, it won't be the relay, and as far as I know there's only one.

Originally Posted by shack

3. If a bad overheat has occured and the fault not cleared (I can't remember the number, but it's hot, you would need a new head after).