Otter Switch for dummies

[K67 KRB]

Chaps,

So my fans come on, but stay on. When I park the car they are atill running full for 40 mins and still not switching off. I'm concerned they will drain the battery. If I unplug the spade from the otter switch they go off and then if I plug it back in they do not come on again.

Should the fans stay on that long....would they switch off eventually and is it likely to drain the battery?

Is there a dummies guide to change the otter switch on a 4.3? Pictures etc. as I can't believe it's that difficult, but I am not that confident with motors.

Cheers.

[Belle427]

Sounds odd as normally the fan relay is ignition fed so should go off.
I'd say the relay is sticking on but doesn't explain what happens when you disconnect the otter switch.
Changing it isn't difficult but do it on a cold engine, you shouldn't loose much coolant if your lucky.
Maybe someone has modified the circuit?

[indigochim]

The otter switch just screws into the radiator if you're quick you wont loos much water. You may find though the issue is the relay for the fans though. I had similar a few years back and mine stuck on just as I was boarding an overnight ferry.

[Loubaruch]

As said above look at the relay. You may find that you cannot unplug the relay from its socket as the pins are effectively welded to the socket. Not uncommon as the fans take a fair amount of current.

[K67 KRB]

Where is the relay situated?

[Belle427]

This is a Chim fusebox but should be the same.
https://www.pistonheads.com/gassing/topic.asp?h=0&...

[Colin RedGriff]

The fan relay is in the main fuse board. Later cars have 2 fan relays as one relay running two large fans was marginal and it wasn't un common fir them to burn out. There should be a fuse board layout for your car in the handbook.

[Wildfire]

Not switching off sounds like a relay issue.

[DVR V8]

Colin RedGriff said:

The fan relay is in the main fuse board. Later cars have 2 fan relays as one relay running two large fans was marginal and it wasn't un common fir them to burn out. There should be a fuse board layout for your car in the handbook.

They all have 2 relays as I found out a couple of years back. 97 models onwards have 2 relays in the fuse board, models up to 97 have one relay in the fuse board, the other relay is wired into the fan circuit and is just hanging loose in the back of the fuse board. Check out a thread I started called FRONT FAN ISSUE. Maybe of some use to you. Dave.

Edited by DVR V8 on Thursday 1st June 19:11