Looking for some feed back on my 1990 f150. The ac is not working so had a question. I had the freon refilled several years ago and the Ford dealership refilled it and noted fill oring needed? not sure was replaced? So the truck was not driven for some time and when i starting driving it again the compressor would click on and off quick and no cooling. I took it to a friend at another dealership and know there must be a leak he refilled the freon and added leak dye. the AC started cooling right away and compressor just clicked on as it engaged normal. We checked with black light and the only dye we saw was around the fill port so must be the oring. So had to wait till it leaked back down to replace. I am concerned as the compresor started clicking on and off quick again then finally stopped clicking in at all. Is this normal once the freon is all out no presure so it stops or could it have messed up the clutch or compressor? I stoped using the AC once the clicking on and off started as did not want to damage the system. But I know it comes on with defrost so it was used some in the winter. Looking to see if anyone can help me out on this.

By the way the truck only has 31,500 miles so is just like new just sitting for a few years must have dried out the seal. I am looking to sell it so wanted to see what to do on the AC.

Thanks

 

The system has a pressure switch. If the freon charge drops to low it will disable the compressor, keeping it from burning up. Most likely if you fix the o ring leak and recharge it it will be all good

 

Thanks I was hoping it was the switch just need ho bite the bullet and get it fixed.

 

76250_4x4?? Will the switch reset once I add some freon or do I have to do something? I just checked the low port and pushed in on the niddle and just a very low hiss so assume it it is about out. Good news only saw some die under UV at needle. I read to add one can if that low the secound till guage is in the green. Just wanted to know if it will kick the clutch in once I add the first can or need to do something first.

Thanks again

 

The system needs to be properly evacuated and re-charged. Being a 1990 the truck most likely came with R12, which is no longer being made, however it can be found recycled. The most economical thing to do would be to convert the system to R134A. You will need new seals, drier, hoses and oil for the system. R134A molecules are smaller than R12 molecules and can seep through the older hoses. There's a leak somewhere that needs to be fixed, topping off the system is unacceptable.

 

The ford dealership serviced it about 6 years ago and not sure what they did the service ticket just said added charge and needs evaporator Oring. When I had it checked at another dealership by a friend he sail looks like they converted it as had the new fill adapter on it already. He just added charge and it worked fine but after awhile it leaked back down.

 

I'm having the same issue.

How much does it usually cost to have the conversion done?

 

I picked up some R134a to add but if the compresor will not come on how will it pull the new in? I tried to pull of the presure swith and jumpered it to see if the clutch will kick in and the rpm went up some but did not kick in compresor. I guess i did the right switch as it it the one beside the fill port up top not at the compressor. Could it be a fuse or I would not think so since it sparked and RPM went up....? It was really low as the gauge did not show any when i hooked it up and it said add half the can if compresor is not coming on so added some and went up to 25lb but still did not come on. I just stoped as wanted some feed back.

Any ideas?

 

That is a loaded question.....

To do it the right way with the proper barrier hoses, new compressor, condenser, evaporator, receiver/driver/accumulator, o-rings and a high pressure retro-fit switch it will run you several hundred dollars.

Do not get me started on those crappy R-134a "replacement kits" that are found at Wally world and the parts stores. Totally worthless IMHO if you are planning on the keeping the vehicle for any length of time. Others will argue those cheap and dirty kits worked for them and their bother-in-law's cousin, but for me or anyone else I know I tell them to leave them alone.

If it were mine, I would look at using an R-12 replacement such as Freeze-12 or some of the other drop-in replacements. For that matter R-12 has gotten back down to something reasonable, I would contemplate keeping it R-12. An EPA-609 certificate course can be found on the 'net for ~$20.

I have used AutoFrost in several vehicles when the R-12 phase-out scare was in full swing. It works fine, but there are better alternatives out there these days.

 

Get a meter and measure the voltage at the clutch. If you jumpered the low pressure/clutch cycling switch correctly you should have +12VDC at the clutch (Assuming you also have the A/C turned on).

 

thanks and yes the ac was on and would i meter it at the plug behind the clutch on the compresor. It did spark so i know it is getting power to the switch. I am selling the truck soon just looking to get it working again to show it is working just just needs leak found to repair. The truck is like new 31500 miles so all else is like brand new just ac is not working as had not been used much over the years.

 

That would be correct. The Black/Yellow wire should have +12VDC (A/C on, low pressure switch jumpered) . The Black wire goes directly to ground. While you are measuring voltage, check the continuity of the Black wire to ground as well.

 

Thats some of the best ac advice i have seen in this forum. Reps sent

 

Sorry doing this by phone on reps. So there is no comments. Take care.

 

I appreciate the support. I pull no punches when it comes to those R-134a "conversion kits". Others may disagree, but in my experience and research those kits are not worth the cans they come in. Don't get me wrong, you may get some cooling operation from them for awhile, but in the long run it is playing with the devil. Some are lucky in life, others are not. I fall into the latter category