A/C issues in 91 previa

[CMB]

I am having issues with the A/c system in my new to me 91 Previa. The A/C button when depressed, lights up, but the engine does not idle up and from what I can tell, the compressor clutch does not engage. There is no cold air. Blower fan works great. There is power at the A/C fuse. There is no power at the A/C idle up VSV. I am wanting to test the AC cut relay, and the magnetic cluitch switch relay, as well as the A/C amplifier, but I cannot locate the A/C cut relay, the magnetic switch relay, or the A/C amplifier. Anyone know where these are located?

I also read another thread while searching with the same issue, and it turned out to be the pressure switch. Would it be ok to jump the pressure switch connector terminal and bypass the pressure switch, or is that inviting more problems?

[CMB]

Ok, so I just bypassed the pressure switch, jumping the connector terminals, and the compressor clutch now engages when the a/c button is depressed, but it still does not blow cold. I peaked into the sight glass with the compressor running and it looks like there is very low on refrigerant. It looked like mostly air, with small amount of refrigerant swirling around the surface of the glass, like watching rain on the window in the eddie behind your side mirror. I guess I need to take it to a shop. Looking through the FSM, it looks like there might be more to fixing the problem, than just recharging the a/c system, like testing for leaks, removing dirt or moisture in the system if present, and purging air from the system. Hope I can find a local shop that will do it right.

[timsrv]

Ok, so I just bypassed the pressure switch, jumping the connector terminals, and the compressor clutch now engages when the a/c button is depressed, but it still does not blow cold. I peaked into the sight glass with the compressor running and it looks like there is very low on refrigerant. It looked like mostly air, with small amount of refrigerant swirling around the surface of the glass, like watching rain on the window in the eddie behind your side mirror. I guess I need to take it to a shop. Looking through the FSM, it looks like there might be more to fixing the problem, than just recharging the a/c system, like testing for leaks, removing dirt or moisture in the system if present, and purging air from the system. Hope I can find a local shop that will do it right.

You are on the right track. If you don't have the equipment then it's probably better to let a shop do it. I hope you find a competent mechanic that's reasonable on charges. Tim

[CMB]

I hope you find a competent mechanic that's reasonable on charges.

If I can't find one, then I might just end up with the necessary equipment

[CMB]

Ok, I took it to the mechanic this morning and he pointed out that this was an r12 system. I didn't know r12 was still being used in 91. So my options are to do a conversion or find some r12. I understand that r12 systems converted to r34a are not very efficient, and i imagine the conversion would cost more than some r12. I want to stick with r12 and it looks like you can find it on ebay and craigslist. What tools would be necessary to get a can of r12 into the ac system? Thanks in advance!

[timsrv]

Yeah, I've had 91s, 92s, & a 93 (all were R-12). Not sure when they switched.........94 I think?. For the most accurate charge a gauge manifold set is preferred. These can be found cheap on eBay: http://www.ebay.com/itm/MANIFOLD-GAU...item4608308185. The cheapest way is to use a can tapper tool and rely on the sight gauge that's part of the Previa (keep charging until bubbles go away). Here's a cheap tool on eBay: http://www.ebay.com/itm/R12-FREON-RE...c6f86e&vxp=mtr. Of course neither of these methods will evac the system or help verify how much oil you have in it. They also won't tell you if there's a leak in the system (unless it's huge). I will usually "chance it" once with this kind of recharge, but if it leaks out in less than 2 years then you'll need to find the leak(s) and fix before charging again. Tim

PS: I should point out that the EPA doesn't look kindly on releasing R12 into the environment. Try to keep it contained. Better yet go to a professional and let him do it. Tim

[CMB]

I asked around and found a shop here in town that will service r12 systems. I thought it was something you had to do in the alley of a shade tree shop, but apparently it can still be done legitimately. It will cost about $180-220, so I will go ahead and spring for that. Hopefully, no leaks are found, and I am back in business with ice cold air.

[timsrv]

I thought it was something you had to do in the alley of a shade tree shop, but apparently it can still be done legitimately.

Oh no, most shops will service r12 systems. They will however charge you a high price for the freon. Some shops will let you provide your own freon, then you can bring a few $20 cans from craigslist (or wherever) instead of paying $50 or more per can from a shop. Tim