Hi how are all of you doing? I tried to search for this problem and didnt see it. I am sorry if I missed something. Thanks in advanced for reading my post. I have a 1989 Ford Ranger XCab 4x4. My A/C is not working correctly. The compressor will not engage until the engine is at or above 3000 RPMs. Anything below the 3000 RPMs, the compressor shuts off and it blows hot air. If the compressor is engaged the air gets nice and cold. The fan is blowing enough air accross the condencer and evaborator. The engine is running on the low end of the normal range on the temp. gauge, so it is not over heating. All the electrical is connected, and in good shape. It is running on the R12 refrigerant, which the system has the right amount (pressure). If anyone has some suggestions I would greatly appreciate it. I have been trying to figure this out for some time, and I am getting frustrated. Thanks for all your help.

 

sounds like your WOT (Wide Open Throttle) AC cut-off relay is bad.

 

Thanks for the post. I will have to check that out. But, if the WOT was bad, wouldnt the engine cut off, or run ruff when it is on full throttle? The engine runs fine, but the compressor doesn't engage until 3k RPMs. Tell me if you think it is still the WOT. Thanks again.

 

The A/C has a relay that cuts the A/C off when the engine is at WOT (Wide Open Throttle). It will not kill the engine, just the A/C compressor.

 

Oh ok, thanks for your help. I think it is located under the fuse box that is under the hood. Is that correct? If that is correct, which one of the I think 3 or 4 relays is it? Thanks

 

Neither of my repair manuals have the fuse box layout of a '89-'92 Ranger. If you have an owners manual, it should be in there.

 

With the research I have done, there are three relays.
- Fuel pump (E3TB 9345 A2A)
- EEC (E3AF 12A646 B2A)
- A/C -- I don't know which one: dealer said:
- (E3TB 13A025 A2A)

Everyone on the forums said:
- (E5TZ 19D572A)

I am trying to figure out which one.

My truck had the fuel pump and EEC relays but the A/C one was missing. So, I guess you were right about what was wrong with my A/C.

IF ANYONE KNOWS WHICH ONE IS THE CORRECT RELAY I AM ALL EARS, AND WOULD GREATLY APPRECIATE IT!!!!!

 

heres an image i pulled off all data for your truck - top of the page it shows the cutout relay.

 

the relay closest to the front is the one that I am talking about (on the left of the 3 relays under the distribution box).

 

Ya, that is the one that is missing. Thanks soooooo much for the picture, you have been a great help!!!! I just wish that picture gave the numbers, nun the less it was a great help!!!!. I am continuing to research but I am coming up with the two different relays, maybe either one will work? (E5TZ 19D572A OR E3TB 13A025 A2A). Well thanks for your help!!! I will let you know what I find out. I might just go with what the dealer tells me, as they might know more then the people on some of these forums I have been talking with, but not always the case ex. you and those minimum wage part guys, that just read the computer. lol

 

It doesn't need a recharge. I put the correct amount of R12 and oil in the line when I recharged it. That was only a few months ago. Also an indication that it doesn't need to be recharged (i think) is when the compressor does engage it is very cold. I just recharged it, when I replaced a hose that was leaking. Yes I do still have R12 as I bought tons of it before it was no longer available. hehehe sssshhhhhhhh!!!

 

I don't know I have not checked it. I should have when I replaced the line, but I didn't think of it. Do you think I should replace it? It probably will help to get the relay wont it? Thanks for your help...

 

Ya I vacuumed the system out, and put the right amount in the system. It is running at the correct psi. both the high and the low. I am at a loss now. I think I might have to go take it to someone. But because it is R12 it is so damb expensive to do anything with it when you take it somewhere

 

do you have any other suggestions?

 

yea sounds like o-tube.

ASE= Ask Someone Else... lol little joke at work. a mechanic i work with is "master certified" and doesn't know ****. to me ASE means nothing more than you're good at taking tests.