intermittent Boxer a/c?

Hi Mr. Parker,

Need to isolate this to electrical or refrigerant charge. A few thoughts:

* Too much moisture in system can cause icing up, which would "melt" when you stopped for gas. Especially on hot/humid day. I would think less likely to have leak in system as function would not return.
* Problems intrinsic to electrical control system: compressor clutch, ground, continuous power supply.

Haynes publishes an "Automotive Heating & Air Conditioning Manual" (ISBN #1850104808) which is an excellent general reference. I would probably start with verifying high/low side pressures.

Hope this gets you started.

Carl

 

Frank, Too litttle freon can cause the coil to freeze up and cause the kind of problems that you describe. If the AC worked well before and is now acting up I suspect a low refrigerant charge.

 

Should have bought an 8 cylinder!!

 

Do you have the vent open?

I don't know how the vent/AC system works on the Boxer, but last week on a drive the AC was blowing cold, then I noticed it was blowing hot from the outside top dash vents, and cold from the middle one!!??!! I finally realized I had the vents to the outside open pulling in hot air from the outside and mixing it with the cold AC air coming out the top dash outlets.

I just re-did my AC and thought something was wrong at first. A quick flip of the lever fixed the situation and all the air returned to cold again.

 

Frank - check your fuses. The 3 fuses on the right end of the right block protect the fans. If they have gotten hot and distorted the block, you may no longer be making contact. Turning on the A/C turns on the middle fan. If that fuse is gone, then your A/C system may be getting too hot. As a result, your high pressure switch in the charged system may be cutting off the A/C.

This has happened to me. Check the fuses before doing anything else. Also, with the engine off but ignition on, turn on the A/C. Do you hear the compressor clutch activate? You should. Let the system cool before doing this in case it is a high pressure situation.

Jim S.

 

Frank -- One (easy) thing you could try when it stops working properly is to leave it running, get out (quickly), and look at the refrigerant flow in the sight glass on the drier and compare it to the "flow" when it's working correctly.

If there's no refrigerant flow when "bad" you could try measuring the voltages on the high/low switch terminals --

no +12V on any switch terminal (relative to chassis ground) -- you've got an upstream power supply (or control) problem.

+12V on one side of the switch(es) but not the other (going to the compressor) -- either the switch is bad, or it's working correctly and the system pressure is getting out-of-bounds.

If things are working correctly, all high/low switch terminals should be at +12V (relative to chassis ground).

 

All sound advice.

One other thing - the 328 has a "low pressure electrical switch" located on the dryer which cuts off the compressor when refrigerant charge is too low to avoid burning up compressor. Not sure if 512i is similar?

Carl