96 GP se - a/c, cooling fan, sensor connection question

[mmcin50]

I just bought a 96 grand prix se with 3.1 engine - sweet little car, 128,000 miles. Previous owner had futzed with a few things, and I'm taking it back to factory specs, one thing at a time.

I'm down to just a few issues, and I think that fixing one or two problems may solve them all.

The driver's side cooling fan had failed, and they went under the relay box in the engine compartment and connected the wires so that both fans would come on when the relay was triggered. I had the darndest time figuring that one out - I restored factory wire config, soldered the wires and taped it all closed, so now the relays both work, fans come on within a second of each other when I unhook the coolant temperature sensor, as they should. And when the engine warms to 210 the driver side coolant fan comes on, and at about 225 or so the passenger side fan comes on - just the way they should.

The problem is this: When the driver side fan comes on, the engine runs rough, and smooths again when it shuts off.

Related to this, I think, is the air conditioning clutch won't come on. My fix-it-yourself air conditioning pressure gauge shows it has a low charge, but because the clutch won't kick in, the air conditioner system won't take a charge to boost it up.

When I started to restore this car, the cabin heater fan would work on all settings, 1 through 5; now it doesn't blow at all. I have seen the notes on the blower motor resister, and haven't addressed that yet but will on my next day off.

And finally, I have found two connectors that are unplugged, and cannot find where they should connect.

So here are my questions:

1. There is a connector coming from a major wire loom under the air filter box - the one in question is about 6 inches long as it leaves the wire loom - it has 3 wires (black, gray, red with black), the plastic is black, it has a round yellow rubber water-gasket, and looks identical to the connector that plugs into the coolant temperature sensor. I cannot find where it should attach.

2. There is another connector coming from a wire loom near the firewall on the passenger side. It leaves the wire loom in the same place the large red wire does that goes to the alternator. This one is about 13 inches long as it leaves the wire loom; the connector is oval with a notch in the middle on one side; the plastic is red, the water-gasket-seal is gray, there are two wires (white, brown with white); it looks as if it has been hanging near the exhaust, and has been hot or melted a little. I cannot find where it should attach.

3. I don't know why the engine runs rough when the driver-side coolant fan turns on.

4. I don't know how to test the air conditioner compressor clutch. I did find a relay near the blower motor, I think it is related to this - the relay functions normally. I don't know where the a/c pressure sensor is.

I have read 105 pages of this forum looking for these answers, and have learned so much about these great little cars. I am just a few steps away from have a very nice - and reliable - daily driver... thanks in advance for your help with this!

Martin

[BNaylor]

Welcome to AF and the Grand Prix forum.

Your post has been moved to the regular part of Grand Prix forum from our Tips & Maintenance subforum.

[mmcin50]

I found the answer today to part of the problem. The connector under the air filter box is supposed to attach to the air conditioner pressure sensor - the previous owner/mechanic had removed the sensor, and left the connector hanging.

I installed a new a/c pressure sensor and plugged in the connector; unhappily, it didn't change a thing. Compressor clutch still doesn't kick in, compressor doesn't turn, engine still runs rough when the driver's side fan turns on, heater blower doesn't blow.

Does the wire described in #2 above relate to this? Does the heater blower have to work before the compressor will kick in?

Any ideas you can share with me?

[hljmesa]

Well, #2 wire on my '97 Grand Prix goes to the tranny.
And I don't think the the blower motor affects the AC compressor.
Could your compressor be ruined due to not being cool enough, ie. the fan problem??

[mmcin50]

Thanks for the ideas, hljmesa. I can't find anything connector #2 will reach, so I'll jack up the car this afternoon and take a look from below this time.

I put a little R-134a in the a/c system, and Mama Mia! The a/c compressor kicked in! Clutch works, low pressure side is cold, high pressure side is hot, just the way it should be!

One thing at a time, I'll get this beauty back on the road.

Next step, I am taking a look at the blower motor resistor board.

Thanks again.

Any ideas why the engine runs rough when the driver-side cooling fan turns on? Anyone?