Fan override switch

Fan override switch

Author
Discussion

Derek Smith

Original Poster:

47,540 posts

263 months

Thursday 7th August 2008
quotequote all
I want to wire in a fan override switch on my 4.0 1993 Chim. I've got a 20 amp switch.

Can anyone help with the best way of doing it or a wiring diagram?

Thanks,

Derek

Blues

8,546 posts

234 months

Thursday 7th August 2008
quotequote all

Derek Smith

Original Poster:

47,540 posts

263 months

Thursday 7th August 2008
quotequote all
Blues said:
Thanks for that.

I note I nearly had to wait.

Derek

griffter

4,141 posts

270 months

Friday 8th August 2008
quotequote all
Do you need a 20 amp switch? If you're switching anything like that sort of current I think you should use a relay.
However, to fit a fan override switch all you need to do is put a switch across the 'otter switch' terminals (routed into the cabin obviously...).

Derek Smith

Original Poster:

47,540 posts

263 months

Friday 8th August 2008
quotequote all
griffter said:
Do you need a 20 amp switch? If you're switching anything like that sort of current I think you should use a relay.
However, to fit a fan override switch all you need to do is put a switch across the 'otter switch' terminals (routed into the cabin obviously...).
I intend to use a relay - I have a couple of spares - but I thought I'd be specific. I didn't want to run a new cable through the bulkhead as when I've done this in the past I've occasionally caused a leak.

David Beer

3,982 posts

282 months

Friday 8th August 2008
quotequote all
take a relay appart and solder to the neg side of the coil and switch to neg. Drill a hole in the relay cover for the wire to emerge.

JonRB

78,018 posts

287 months

Friday 8th August 2008
quotequote all
To be honest, you don't really need one.

I had one fitted by Hawthorns as part of their desperate attempt to cure my overheating problems back when I got the car (back in 2001).

However, once Dave Batty had got his hands on the car and replaced the otter and thermostat with lower temperature versions and fitted a re-cored rad, I never needed the override switch ever again.

Ribol

11,794 posts

273 months

Friday 8th August 2008
quotequote all
Derek Smith said:
I didn't want to run a new cable through the bulkhead as when I've done this in the past I've occasionally caused a leak.
Why not just go direct to the relay/relays in the fusebox?

No water leaks and no relay required.

Derek Smith

Original Poster:

47,540 posts

263 months

Friday 8th August 2008
quotequote all
JonRB said:
To be honest, you don't really need one.

I had one fitted by Hawthorns as part of their desperate attempt to cure my overheating problems back when I got the car (back in 2001).

However, once Dave Batty had got his hands on the car and replaced the otter and thermostat with lower temperature versions and fitted a re-cored rad, I never needed the override switch ever again.
I've had no overheating problems as such. I ran for four hours in London Thunder with the fans on, but I've found with previous cars that if you turn on the fans when you first hit a traffic holdup you can keep the underbonnet temperature more reasonable. I've got an early Chim with the smaller vents and can't help thinking that they were changed for a reason.

I've fitted them before on other cars, a Rover 420, Scimitar and a Ginetta G32, and liked the reassurance.

David Beer

3,982 posts

282 months

Friday 8th August 2008
quotequote all
there is a much better solution , fully automatic, you do not need an over ride, but of you do want one do as I said.