89 Grand Prix ac/fan problem

New guy , lurked the forum .Seen a lot of good post

Now I have a problem with a 1989 Grand Prix fan ac system cannot figure out .

First of all trying to get the fans working , checked each fan seperately hooked to a battery both work , fuses are fine . I unplugged ect at thermostat housing and driver side fan comes on then pressed AC max button and the fuse blows.
Should both fans come on after 10 2nds or so after unplugging ECT??

I swapped over to R134a freon , by hooking clutch directly to a battery supply and running the primary fan when needed to cool engine. The Ac system took in 2 cans of freon , with this set up .

I then hooked up the compressor clutch wires and plugged primary fan wire back in . Started engine to try and get in another can of freon , pressed the max ac button and the #9 10 amp fuse blows on the passenger side under hood fuse panel . This happened with the ECt plugged back in .

I also swapped the relays around on the #1 and #2 fan , the driver side fan still worked so the relays are good .

Totally stumped on this one anyone have any ideas , figured I got the 2 cans in with the battery hook up , that way the ac pressure cut out switch would work with the 3rd can (hooked up with the on car wires /

Any ideas:banghead:

1989 Grand Prix 3.1

Anybody ran into a problem like this ?? Traced the wires coulnt find any bare spots .

(1989 Grand Prix 3.1 V-6) - First of all trying to get the fans working , checked each fan seperately hooked to a battery both work , fuses are fine . I unplugged ect at thermostat housing and driver side fan comes on then pressed AC max button and the fuse blows.
Should both fans come on after 10 2nds or so after unplugging ECT??

The primary fan should turn on as soon as the CTS is unplugged. The secondary fan will likely only turn on with the compressor request AND the A/C intermediate pressure switch rise (at 200 PSIG).


I swapped over to R134a freon , by hooking clutch directly to a battery supply and running the primary fan when needed to cool engine. The AC system took in 2 cans of freon , with this set up. I then hooked up the compressor clutch wires and plugged primary fan wire back in. Started engine to try and get in another can of freon , pressed the max ac button and the #9 10 amp fuse blows on the passenger side under hood fuse panel . This happened with the ECT plugged back in .

I also swapped the relays around on the #1 and #2 fan , the driver side fan still worked so the relays are good .

The fan relays are interchangeable, so that should have had no effect unless one of the relays is damaged.

Fuse #9 is for the instrument cluster, which includes the HVAC control console. Selecting the MAX AC function will cycle the compressor on, just like using the NORM function. However, MAX AC also grounds the vacuum control solenoid for the recirculation air damper. In the event the recirc solenoid is damaged, use the NORM selection instead of MAX AC. If the fuse remains intact by using the NORM selection and blows in MAX AC, that recirc damper vacuum solenoid and/or its circuit are highly suspect.

Totally stumped on this one anyone have any ideas , figured I got the 2 cans in with the battery hook up , that way the ac pressure cut out switch would work with the 3rd can (hooked up with the on car wires /

Any ideas:banghead:

Beyond the evident electrical problem(s), you may want to be very cautious about adding a third can of R134A to the system. R134A systems typically operate with a lot less refrigerant load than R12 systems, and the only safe method is to use a gauge manifold to monitor both low- and high-side system pressures as the system is charged. R134A systems are a lot less tolerant of overcharge, and significant component damage and personal injury can result from overcharging.

I'm hoping the expansion control orifice was also changed as part of the retrofit, or you may have less than satisfactory cooling from the system with the R134A.

Thanks for the reply .

The primary fan does turn on , when unplugging the ECT .So at least I know that works.

As for the vacum solonoid/cicuit , never thought of that . I'll have to check and see if its listed in the chiltons (doubt it ) , or what am I looking for ?

Also for the 3rd can , I should of explained it better . I had the 2 cans in and only need a little bit more of the 3rd , according to the gauge and temperature indicator I was useing .

Thanks for the heads up on the overfilling :bigthumb: