Just completed installing a '94 vette LT1 in my 85 Elky.... seems to be working out well, most of the bugs are worked out. One problem is turning on radiator fans when a/c compressor turns on. I think the fans come on (in a vette or camaro) when the a/c high side switch sees a certain pressure and an evaporator temp sensor is sensing above a near freezing temperature (inputs to the PCM).

Any ideas on how to turn the fans on either through the PCM, or through hardwiring to the fan relays?

Many Thanks!!!!!!!

Simplest way would probably be a to activate the fans thru a relay. Activate the relay with a circuit fron the AC compressor clutch wire.

Here is some wiring that might be helpful. You won't need all of it but maybe it will give you an idea.

http://farm2.static.flickr.com/1431/537022814_7bd101934c_o.jpg

Many thanks for all the help! I started probing around on the relays and discovered I could ground one of the relay posts and the fans would come on. So I just used a relay and controlled it using the A/C compressor circuit, i.e. voltage from the compressor circuit closes the relay, grounding the fan relays, which turns on the fans.


Again, thanks for the replys!!!

Well, duh!!! Just looked at your post Mike P.....that's exactly what I did!!! Works like a charm,............sorry, sometimes I'm a bit slow on the uptake.

Thanks again!!!