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        General >> Problems >> Wiring up a relay?
        
(Message started by: Anto_95 on Nov 8^th, 2006, 3:17pm)

Title: Wiring up a relay?
Post by Anto_95 on Nov 8^th, 2006, 3:17pm

The Thermatic fans have never worked properly in the Scorpio, PCM does not turn them on, so they're wired up direct from the battery to a switch under the dash. From the battery + is a fuse holder with a 30amp fuse, - direct to fans and the wire used is far too light. Only use this in heavy traffic. Have burned out a few switches and there's is a danger of fire if I forget the fan is on. I was told to fit a relay to take the load off the switch. Relay is a Bosch 4RA 30amp with terminals 30, 85, 86, and 87. I know 30 is power from the battery and 86 is to the switch, 85 earth, but 87 is power out? Anyone know the correct way of wiring this up for this situation.
Regards,

Anto

Title: Re: Wiring up a relay?
Post by martin_rowe on Nov 8^th, 2006, 3:56pm

use an ignition feed via a switch to pin 86, pin 85 to earth, battery feed via a fuse to pin 30, pin 87 to the fans. that way fans can only come on with ign on, & will go off with engine off.

Title: Re: Wiring up a relay?
Post by TiberiuS on Nov 8^th, 2006, 5:07pm

It would be much easier (and safer) to treat the cause rather than the symptom.

A second hand PCM can't be that expensive, much safer and much less hassle.

Regards, Bruce.