Ok to run with 12v+ connected to Compressor?

Wife's 2002 330i has A/C problems. The compressor will only work if 12V+ is connected. Is it ok to rig up a switch to manually turn on compressor for a few days? She will be out of town for work and needs the A/C.

I've taken the car to two reputable shops and they can't figure out what the problem is. One shop refilled the refridgerant, still nothing. I bought a replacement A/C Head Unit thinking that would solve the issue, nope. Any ideas would be appreciated.

Thanks all!

Chris

The best solution would be to have the car scanned with a BMW GT1 tool. Maybe you have an issue with the black box on the fan shroud which might be the cause.

Ok, but is there a way to jumper it for now? Who besides the dealer would have such a tool? I'm in Buffalo, NY area.

Thanks for your speedy reply!

Chris

I would give the shops that specialize in European cars a call. Have you tried searching for "ac compressor not working" or something like that? I never had the problem so I can't be of any more help than what I am now. If you do know how to wire the switch for a few days go for it because it's going to be very bad for the next few days. :/

Originally Posted by Solidjake

I would give the shops that specialize in European cars a call. Have you tried searching for "ac compressor not working" or something like that? I never had the problem so I can't be of any more help than what I am now. If you do know how to wire the switch for a few days go for it because it's going to be very bad for the next few days. :/

Problem with that is there is no monitoring of the high pressure side then. The AC compressor NEEDS to cyle to reduce pressures. If the High side pressure goes to high you will DAMAGE something!!!

I would NOT do it unless I had gauges hooked up to monitor pressures

Originally Posted by jbeurotech

Problem with that is there is no monitoring of the high pressure side then. The AC compressor NEEDS to cyle to reduce pressures. If the High side pressure goes to high you will DAMAGE something!!!

I would NOT do it unless I had gauges hooked up to monitor pressures

Thank you. OP there you have it.

Wow, uber speedy responces. Thanks, I will not be doing that. I'll try picking up a low pressure switch and go from there...

just get the IHKA scanned to see what the problem is. a reputable independent garage or the dealership can do this. throwing parts at the car is not a smart way to diagnose and will cost way more money than a diagnosis.

@unibagel

How did you diagnose or come to the conclusion that your A/C compressor only comes on with +12V?

Are you sure that the freon is not missing? I am not sure if E46 has the same system or different but most of the cars do have this switch: there is a low pressure cut-off switch which doesn't let the compressor turn on if the system has low/missing freon.

I can see that it is not coming on and the shop ran a wire to it and it started.

yes The first shop filled it and the second shop verified there is indeed freon in there...

What else???

Originally Posted by BimmersGarage

@unibagel

How did you diagnose or come to the conclusion that your A/C compressor only comes on with +12V?

It is not not safe to hack it, it can damage your ac compressor, compressor clutch, hoses.etc It will damage the parts which are weak.

If you really want to do it, you need to hack the AC condensor fan also (if equipped).

OP,
I believe Rizwan1377 is correct on this matter. Forcing the compressor to activate when there is something wrong with the A/C system, would be a most costly venture.
If freon is low... I believe the system will not allow the compressor to engage.

Like Solidjake and jbeurotech have stated, better to take it into a BMW specialist/dealer to have the codes pulled or system checked properly.