1989 Ford F250 7.5L
Where do I start at diagnosing why my A/C compressor quit engaging. Are there fuses that control it? It use to work, I have owned the truck since 1992. When it did work the compressor was noisy when it enaged, I'm guessing it just went out and I need a new one. Any help would be appreciated, thanks!!
Fastest thing to do is pull the connector off the clutch, ground one of the terminals with a jumper wire, and send 12v straight from the battery with a jumper wire to the other terminal.
If nothin happens, ac clutch bad. Get a click, we can start troublshooting wires.
If freon is low, it won't engage. You may have a leak. There should be a pressure switch. If you were to jumper the terminals and it works, you are low on freon.
If you can nail down problem parts, you can replace them, but after that, let a pro oil and charge the system.
If the "only thing wrong" is that you're low on freon, you've got a leak. Let a pro find it, fix it, then recharge the system.
The pressure switch was bad in my '93, so my A/C didn't work (bad and leaking). I took it to a shop, and for about $375, they replaced the part, converted the fittings for R134a (couldn't get R12 and none of the mechanics even kept their R12 gauges at the shop any more), evacuated the system and then charged it to spec. It's been working great since--about 2-3 years now.
That's compared to my '90 where I basically sunk $400 into it with a conversion kit, several cans of R134a, then a new compressor...and still had a system that leaked out in 2-3 days. Leaks only get bigger and more expensive on A/C systems, never smaller.
Jason
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-1990 F150 XLT Lariat LB 302 2wd AOD 3.55 open (former work truck, gone, but not forgotten)
-1993 F250 XLT xcab LB 351 2wd E4OD 4.10 open (parked, tranny issues)
-1989 Mazda B2200 SB 2.2L 2wd 5-speed (work truck)
I jumped the connector off the pressure switch and the compressor fired up!! So it looks like I am low on R134 and must have a leak somewhere. Thanks for everyones help and advice!
Not so fast guys!
AC repair is very doable by a DIYer with some basic AC knowledge. The biggest problem with DIY AC repair is lack of understanding of the system and cutting corners. The rack of "magic juice" at the parts store often gives the impression that AC repair is cheap and easy if you use these products. Sealers, boosters, stop leaks, eyc. just plain don't work except to flush your wallet. The same with the "tools" on that rack near the parts counter.
On graven57's 89, there's obviously a leak. At nearly 20 years old every o-ring in every hose connector needs to be replaced for the whopping cost of about $8. Close inspection of the compressor and condenser, hoses and hose crimps for oil or staining will uncover most other leaks. He can rent or borrow the proper tools (vacuum pump, manifold gauges, can tap, etc.) and repair the system as well as any shop.
It ain't rocket science, just a system that most folks are intimidated by until they are familiar with it. Check out Automotive AC Information Forum - ACKITS.COM. It is an excellent DIY MVAC site.
Hey, Quicklook2- Howdy neighbor!
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