HELP - Were is the cooling fan fuse / relay

[AJV]

On my way into work I picked up a newspaper across my air intake and for the first time I saw my temp gauge go beyond 1/2! When I managed to pull over and stop as I was stuck in traffic for a while the temp was a couple of needle widths below full. To my dismay I noticed the fans were not on! I suspected the clogged intake led the fans to run long and hot and they have blown a fuse. I found and replaced a blown 5A fuse below the binnacle which runs the eclectic cooling water pump when I short the fan sensor switch, however the fans don’t run! The fans work as I have unplugged them and applied 12V from and external source.

My question is do the fans have separate fuses (I have seen reference to this on the forums) and where can I find them, also do they run trough relay(s) and if so where are they located. I don't have an electrical manual circuit diagram.

By the way while I am at it does anyone know what the little button on the mirror adjustment gimbal switch does apart from illuminate the little amber LED next to it?

Many thanks in advance!

Ariez

[RayD]

If it's too small to see PM me your email address...

[GeoffSmith]

By the way while I am at it does anyone know what the little button on the mirror adjustment gimbal switch does apart from illuminate the little amber LED next to it?

Door mirror de-icing.

[Doug]

yes, it is supposed to heat the elements under the side mirror glass -- you can feel it get hot with your hand if it is working right.

[Doug]

there's tricks to energise the fans to be sure the circuit is working -- it is written in the forum somewhere, but I believe you just need the ignition on and then ground the single wire coming from the radiator fan thermal switch (see pic) next to the t-stat housing



that should cause both fans to turn on and run until you unground them -- with the ignition off it will cause the coolant auxiliary pump to run

Regardless, you should need the coolant temp up to about 3/4 on the gauge before the fans are supposed to kick in -- can't remember for sure but it is 108 degrees or so that activates the fans

if the above test works then the fans are likely fine and the car was actually not hot enough yet to turn the fans on when you saw it before.

[AJV]

Firstly let me say I am blown away by the speed of response from you guys, it is very heartening.

I have checked all the connections fuses and relays (I can see) in the cooling circuit. But alas I can't get the fans to come on, there is simply no power going to them, I have checked with a voltmeter. I checked with ignition on / off and also with the engine running shorting the Rad fan thermal switch does run the electric pump with the ignition off but just I cant get the fans on. I thought it may be related to some required combination of conditions with the ECU so I even let the engine run to fully hot (until it was just starting to vent coolant).

This is perplexing (I am being polite), am I missing something or is there a Lotus / GM secret. This is my first Lotus / GM car I am a converted Alfetsi and have been a hobby mechanic for years including restorations. The Elan having Japanese power and electrical systems I never imagined I would have this sort of problems.

Any Ideas?

Thanks in advance,
Ariez

[ESM]

I suspect the 30A fuse on the supply has gone. The fuse is located in the maxi fuse box.

Its a bit of a pig to get to. I have a vague memory it might be reachable if you take out the radio, in RHD cars at least. The manual says you have to take the fascia off....

At any rate click the manuals link above and request a password to download them, then you'll have access to all the circuit diagrams and instructions available.

[Doug]

good idea above -- you may have to do that to fix a fuse it seems

you can always find the leads into the fan and jump the 12V battery directly to the fans to prove they work, assuming they do then you know the fans are okay.

then check the leads to the fan with the voltmeter, short the thermal switch and prove that you get no current to the fans -- then this would prove there is a fault in the circuit to the fans themselves

from your noticing the coolant pump will work shows that the circuit from the thermal switch to the coolant pump does work

sounds like Alan may know the circuit, but otherwise check the wiring diagram and just trace the fan circuit and perhaps it leads you to exactly what Alan said above . . . (the fans do take a big load or current so they could certainly pop a fuse)

[GeoffSmith]

If the coolant pump is working, it's not the main fuse - maybe the relay.

As Alan says, sign up for access to the manuals area.

[AJV]

Thanks for your help guys, I think I've done it all now but still no success. I have:

* Checked the main Maxi fuse box (Tip remove the radio and push out the ash tray unit form the fascia it can be glued back) I am now an expert in keyhole surgery and audio system theft, all fuses were OK.
* Rechecked the fans with a direct connection to a battery they sing sweetly.
* Swapped over the common headlight relay with the fan relay in the binnacle, headlights work normally, but fans dont!
* Noticed the following strange phenomenon with the ignition on and the Cooling Fan Temp Switch shorted. If both fans are unplugged the circuits to the fans register 12V with no load and will light a small indicator bulb. If one or more fans are connected the voltage drops to 0V. All fuses are OK.

Anyone have any more ideas?

P.S. I have just got my password and downloaded the manuals, I had a quick skim of the relevant pages nothing stands out.

[GeoffSmith]

If you're dropping the 12V when you connect the fans, it's most likely a bad joint somewhere. It's common to both fans so there aren't many places it can be. I'd suggest checking the voltage progressively back towards the main fuse.

Geoff

[ESM]

Yeah I think a corroded connection could be it. Separate the connector blocks in the fan circuit and see what sort of condition they're in.

[Doug]

bad connection or ground could be it.

[GeoffSmith]

Thinking about it:

1. Neither fan works

2. Voltage disappears when fans connected

Therefore it can't be an earthing issue and has got to be a bad common connection, i.e between the main fuse, through the relay to the two 15A fuses.

Geoff

[AJV]

Many thanks guys.

The fault was traced back to a corroded earth connection the two fan earth lead split out from the harness and are grounded with the same ring crimp to the radiator frame. The bolt sits right in front of the turbo unit and is a pig to get to. Having narrowed down the field this afternoon it took me 15 min to find the problem and 2 hours to get the bolt off followed by another 2 hours to try and put it back on I eventually extended the cable and have grounded it to the engine block itself.

On the bright side I now have am in depth knowledge of the electrical system.

[Paul.P]

On the bright side I now have am in depth knowledge of the electrical system.

& fans that work !, well done