Ok, time for help !!! I have a ' 76 that I dropped a ' 94 lt-1 into. The A/C problem I have is that the condensor " overheats " , and cuts off the high side of the system . I have 2 electric fans on the radiator . They don't go through the computer !!! They are connected to 2 relays that pic up the temp. from the head .

Any ideas as how to keep the condensor cool ? I was thinking of running one fan through a relay , and connecting it to the a/c harness . When I use the a/c, the fan would turn on. The second fan would cool the radiator, as would the one cooling the condensor . Sounds odd I know, but can't figure anything else out.

They need to be connected together so they cut in if the A/C needs cooling or the engine needs cooling.  I'd be looking at your 94 wiring and see how it is done there so you can adapt it to the 76 wiring.

The last thing you want to do is overheat the engine.  The A/C will just get hot if it overheats but the engine will have big problems if you allow to get too hot.

Just hook up the fans to come on when the compressor is running with another relay & keep your current water temp setup. It's best to use both fans together not seperate. They might come on when your cruising, but at least you're not wrecking anything. You could also install another senson in the condenser & have the fans kick in when either one get to hot.

Alan

The wiring is a Street and Performance harness . There are no connections for the a/c in that harness . That's why I have the relays for the radiator fans ( a DeWitts set up ) .

Is it possible that the pressure is too high ? Would that be causing the condensor to overheat ? If so,  what should it be, since this is no longer a stock set up .

Try putting an override switch in line & turn on the fans when you run the air if that works then just wire it up to come on with the compressor. If you're not sure how to do that I can look see if I can find a DeWitts wiring diagram & show you what to do.  It is possible for the pressure to to high & if you're not sure just take it to a A/C shop & they can check it in a matter of minutes if it's R134 it could case serious damage to the system. But from what you describe I think it's not enough of air flow especially at low speeds.

Alan

I just went to dewitts home page they say the blue wire connect to the compressor clutch http://www.dewitts.com/download/Fan-PWM.pdf Give them a call they seem like they can solve your problem

I hate to ask a stupid question but I'm hoping both fans are on the same side of the radiator?  It would be silly to have them both working on either side with them both blowing, if you get my meaning.

I'm presuming you have a side by side set up, so my stupid question would definitely be stupid.

Never heard a stupid question... Both fans should be mounted side by side between the engine & radiator pulling air through the radiiaton. Do you have your front between the hood & radiator closed off. No air should be allowed to get around the radiator in a vet or you will have heating problems it must be blocked & when you turn on that air conditioner those fans should come on. Do you still have or use the shroud? I have the presssure setting at work  I'll see if I can get them to you.

Alan

Both fans are side by side . It is a DeWitts radiator/fan set up . Since they are electric fans , they came with , shall we say, small shrouds .

I contacted DeWitts . They say the simplest way to fix the problem is to install another relay . That relay would be connected to the a/c compressor ( and fans ) and kick the fans on when the a/c is used .

As for the R 134 pressure, I'm still not sure the proper amount .

I have a chart at work & I'll see if a 94 vet is in there if so I'll send you the low & high pressures for the different temp & humidity readings. Sounds like everything else is right on though. How do you like it with the newer engine...probably runs much better. I know those engines are pretty easy to soup up.

Alan