I guess I know nothing about A/C

[mjbst111]

My A/C only blows cold air when I'm going highway speeds. When i stop it gets warmer. It’s still kind of cold but not cold.

Well at least it was really cold last summer at highway speeds.

Anyway I figured it was because my auxiliary fan did not work. So I bypassed the radiator's temperature sending unit and the fan went on high speed. I'm thinking problem solved! But I went in my car and it’s still not cold when I’m sitting there.

Do I need a recharge? I read in the Haynes manual that if you touch somewhere on the system like right after the condenser if it is cold then it need recharged or something. Can anyone tell me a good clear way of finding out what is up?

My compressor is definitely switching on and off. Actually it switches on and off maybe too often. It’s pretty annoying. I'll drive down the highway and it will click on for 15 to 20 seconds then off for 15 to 20 seconds....

A/C is beyond me. Anyone??

Thanks in advance....

 

[epj3]

When you are just sitting there, there is not much pressure in the system.

If it's not as cold as it used to be, take it somewhere and have them flush then fill the system (unless you have already gotten it converted to the new enviromentally friendly stuff) and it will work like new.

 

[Kether]

Check and make sure the electric radiator fan turns on when the A/C switch is on, it's the fan just behind the grille. If it doesn't turn on, check the fuse, make sure the fan moves freely (i.e. motor isn't seized), if the fan still doesn't turn, the resistor may be to blame. It's a piece of metal about 10cm in length, probably secure to the side of the fan's housing. It has two wires coming out of it. It can be tested, but they are usually to blame in these circumstances. It'll cost you about $30 at your BMW dealer. My advice is to mount the resistor somewhere where it will be less exposed to vibration. The resistor inside the metal casing is ceramic, and it it develops even a hairline crack, it will fail.

Good luck, let us know if that was the issue.

 

[mjbst111]

Hi there everyone... Its been a while.

Anyway, i'm diggin this up because the same thing is happening with my e36 now (last car was a 1991 e30). Anyway for the e30 i bought a new resister but wrecked the car before i could put it in and test it.... so those are my finding. Sorry not helpful.

In the e36, the fan won't go on at all no matter what i jumper or test. I think i might need a new fan but i'll keep everyone posted. Still have to hot wire the fan and see if it spins.

 

[Doughnut]

read in the Haynes manual that if you touch somewhere on the system like right after the condenser if it is cold then it need recharged or something.

With the engine running, and the A/C on put your hand on both the inlet and outlet pipes leading to the A/C compressor.
One hose should get too hot to touch and the other should get too cold to touch, if they dont, or the cold one only gets slightly 'cool' you have a leak somewhere in the lines or you need a system flush and refill.
Peace.

 

[mjbst111]

Thanks, I'll check that out.

only when i touched two wires with hot and ground did it do anything and it spun at high speed. Any better suggestions for fab troubleshooting?