Wiring dual cooling fans with A/C compressor removed (M100)

[John Tsakas]

Hi everyone,

I recently managed to fix an intermittent ECM relay issue on my Elan M100, but now I am trying to sort out the cooling fans.

Currently, only the Left (main) cooling fan operates when the engine gets hot. The Right fan does not turn on.

The previous owner completely removed the Air Conditioning compressor. Right now, I have two loose wires hanging in the engine bay where the compressor used to be:

One Black/Blue wire

One Red/Black wire

I want to make the Right fan work as an auxiliary cooling fan to assist the Left one, since the A/C compressor is gone.

What is the best way to achieve this?
Thank you

[TorqueHorse]

Not seeing a photo, and not knowing the spec of your car for sure, but I think the Red wire went to the AC compressor clutch, and the Black with Blue goes to the pressure sensor at the bottom of your power steering pump.
Also, for a FED car, the fans are already wired together and both come on/off at the same time (regardless of if the request was coming from the AC being on or the coolant temp getting too high). So maybe it is just a matter of looking at the wires that go into your non-working fan? Could be that just that one's motor is burnt out?

[Simon_P]

Hi John,
Both fans should work together.

Nothing to do with A/C - don't use the wires if you don't have A C.

Using a switch to ground the fan relay is the way to get the fans to come on when you want. clemo did a writeup somewhere.

[Simon_P]

viewtopic.php?f=35&t=11970&hilit=fans

[John Tsakas]

Not seeing a photo, and not knowing the spec of your car for sure, but I think the Red wire went to the AC compressor clutch, and the Black with Blue goes to the pressure sensor at the bottom of your power steering pump.
Also, for a FED car, the fans are already wired together and both come on/off at the same time (regardless of if the request was coming from the AC being on or the coolant temp getting too high). So maybe it is just a matter of looking at the wires that go into your non-working fan? Could be that just that one's motor is burnt out?

Thanks for the reply. I tested the right radiator fan directly with 12v battery and it works perfectly. i also connected the plug from the left fan over to the right fan, and it worked fine that way too. Mysterious things

[John Tsakas]

Hi John,
Both fans should work together.

Nothing to do with A/C - don't use the wires if you don't have A C.

Using a switch to ground the fan relay is the way to get the fans to come on when you want. clemo did a writeup somewhere.

The car actually has a manual switch inside that activates the fans whenever i want, which was likely installed by the previous owner.
When i flip the switch, only the left fan turns on. Also, when i turn off the ignition, the auxiliary water pump runs normally.
The car cools fine while is moving due to airflow, but as soon as i stop at a traffic light, the temperature starts rising because only one fan is operating. Since i already proved the right fan motor is healthy by jumping it, i suspect the issue is corroded or loose connections at the fuses or relays.
is there anything else i might be missing? i havent't checked under the steering wheel /footwell area yet. Are there any fuses,relays or connectors down there related to the cooling fans that i should look into?

[peteoddcar]

The cooling fans are individually fused most likely the fuse B3 B4 in the small binnacle (4 relays 4 fuses) fuse box has blown. I think the Fed cars have the same set up no reason to alter it. Access through dash top driver side.
The ac wiring is irrelevant if it’s all standard and no not been messed with.

[John Tsakas]

The cooling fans are individually fused most likely the fuse B3 B4 in the small binnacle (4 relays 4 fuses) fuse box has blown. I think the Fed cars have the same set up no reason to alter it. Access through dash top driver side.
The ac wiring is irrelevant if it’s all standard and no not been messed with.

Thanks for your reply. But both fuses 15 are ok

[Tuga2112]

cehck wire continuity (and resistance) between fuse and plug.
also inspect plug for corrosion

i had just repaired the light bulb on my MR2 2 days ago. it turned out the issue was a poor connection between the bulb and the contacts as well as the plug at the bumper end contants having mild corrosion.

[peteoddcar]

The cooling fans are individually fused most likely the fuse B3 B4 in the small binnacle (4 relays 4 fuses) fuse box has blown. I think the Fed cars have the same set up no reason to alter it. Access through dash top driver side.
The ac wiring is irrelevant if it’s all standard and no not been messed with.

Thanks for your reply. But both fuses 15 are ok

Supply on both fuses ?
One of the fan grounds rotted away check with a test lamp the supply to the unopened fan
There’s an inline connectors in front of the A pillar under the wheel arch liner but these rarely cause issues
The FED front end is quite different to our cars so possibly there’s a jumper harmess but honest can’t recall

[Tuga2112]

The cooling fans are individually fused most likely the fuse B3 B4 in the small binnacle (4 relays 4 fuses) fuse box has blown. I think the Fed cars have the same set up no reason to alter it. Access through dash top driver side.
The ac wiring is irrelevant if it’s all standard and no not been messed with.

Thanks for your reply. But both fuses 15 are ok

Supply on both fuses ?
One of the fan grounds rotted away check with a test lamp the supply to the unopened fan
There’s an inline connectors in front of the A pillar under the wheel arch liner but these rarely cause issues
The FED front end is quite different to our cars so possibly there’s a jumper harmess but honest can’t recall

in my car both Fans ground on the same eyelet... which happens to be in a surprisingly dificult location to access

[peteoddcar]

Hi
I’ve had a video call with John - the problem with his car is not straight forward as far as we can tell. I have sent him a a temp fix ( which is probably good enough to be permanent)
There’s a few things on that that don’t stack up with the diagrams, I’d like to view the car and may well do although it’s in Athens !
Mrs B might be up for a short city break to in the Autumn !