Automotive Air Conditioning Information Forum

Mazda b2500 2.5L. Need to get all the selections for AC compressor. 1. compressor cluch clicks on,off,on,off,etc. 2. have pretty good cold air into cab, mechanic says I have freon but they can't check for leaks because the clutch fan is not working? 3. need to see if I have the vacuum tubes in right place, when/how, does the door in the heater box open/close. 4. when I disconnect the power to compressor I get great heat, pluged in, not so much.5. With everything back to normal, should I see HCV move with the movement of the temp. control switch? I think my cold air could be colder but the clutch doesn't engage for very long so the air won't be THAT cold? Need answers, I'm not much on A/C, hope this forum works, need all the help I can get. Thank you.

It sounds lie your compressor clutch is short cycling.

There are a couple of reasons for that to happen, either low ambient temperature or low charge level.

Some more information would help. What sort of temperatures are you seeing where you are located? What model year is the vehicle?

You say the clutch fan is "not working" - that is a broad statement. If it is not working well it does affect the cooling capacity of the system. Can you describe what is wrong with the fan?

It also sounds like the doors and actuators that control air flow in the cabin may not be working properly. Vacuum leaks on older cars are common problems in that area.

You should consider an Alldata subscription to get the Factory Service Manual for your exact vehicle to sort out the vacuum controls and other issues specific to your car. You can purchase a one month view for about $20 - screen shot everything you think you will need later.

Great,thanks for the reply. I went to a shop to test for leaks, dye and all that stuff. Guy came back and said they couldn't chk for leaks cause my fan clutch wasn't working. He sort of said I had plenty of Freon, don't know how he knew unless he vacuumed it and weighed it? He said he could stop the fan by hand with engine running, I don't think the engine was hot enough to engage the fan, but? For 40 bucks I'll get a clutch. When you ask everyone says low Freon but not so? per mechanic. I've replaced every vac tube that has to do with heat/air. What I haven't checked is the workings of the HCV and that door to the blower motor under the glove box. Need extra eyes and hands. When I disconnect the power to the compressor the clutch stops cycling and I have great heat in all the heater vents. When I reconnect the power the clutch cycles and the a/c is not as cold as it should be, I think, plus the heat temp goes down @10*, I think because the a/c is on for seconds which pumps cold air for seconds.The temp switch works, I guess, withe the compressor unplug for max heat I can adjust the temp by the switch.The a/c control isn't a good judge because of the compressor clutch cycling and it doesn't stay engaged long enough for good a/c. So, I guess I covered everything, what's your opinion? Thanks.

Sorry, 2000 Mazda b2500 with 2.5L engine. I'm in Fl. and it was 79* when I did all I could do. Pretty lame temp gauge so it was a tad below half way. New thermo and a crude thermometer only goes to 120* Hoses sure feel hotter then that. Inside temp on heat is @ 105* and the a/c is @103*. Who knows what a new clutch fan will do. Thermostat rated 192 and I'm 99% sure it's working, have heat in all the right hoses. Both heat sensors work, PCM and the one to the dash gauge.Meter and hot water. Sorry I almost forgot what you asked me for.

Ok, the fan clutch is shot. With a 79f ambient you need the fan. Replace it.

The third reason for short cycling would be cycling on the HPCO - because of high pressures caused by poor condenser performance.

Try spraying some water on the condenser while the system is running, and see if the cycling stops.

Really the best way to work on your own A/C is to know the pressures. A gauge set is not hard to use or expensive. You need both the high & low pressures to diagnose a system properly. The site sponsor has good prices on tools & parts:

http://www.ackits.com/r12-brass-gauge-s ... rch=mt0417

Quickly pays for itself. Two trips to the "A/C Shop" @ 45 bucks each.

Is the condenser original to the truck?

srkreutemazda wrote:2000 Mazda b2500 with 2.5L engine. I'm in Fl.

Also know that this vehicle is really a Ford Ranger, and made in USA. Some of the Rangers had factory AC, some had dealer-installed, parts were not necessarily the same.

Thanks bohica,guess you caught my goof-up. I said a/c temp was 103* should have said @ 50*. Any way, it's a new fan clutch for me. I don't really need that gauge package. Here in FL. there are a few places that do a/c checks for free.Not leak checks, but pressure tests. Not to mention the retired a/c guys that can do auto a/c checks as well. You didn't mention my question about the function of the HCV and that door in the heater box under the glove box?. I think the temp control in dash controls the HCV, I think. When i look at the HCV unit while the temp switch gets turned, what should I see? Thanks again.