ac problems scorching here in texas
 

Hey Ive relied on this forum for so much and its always worked, thanks for those of you who have helped. Right now my ac is going nutz. It has always been good to me till recently. Two weeks ago the light went out, it blew a fuse and stoped blowing cold. I replaced the ten amp fuse on the left side of the glove box and it started working perfectly. Today(two weeks later) it blew the fuse again. I replaced it and it blew right away. The fan and heat work perfect still, but its like 99 here in texas and my son and I are dying. I need help please. I searched alot and I didnt find any similar posts. I know there are supposedly two relays right? There is one above the two fuses next to the glove box and where is the other? Ive read that it could be on the other side. Could it be one of these? Any advice is definately appreciated. Oh yeah, its an 89 3.0 4runner. Thanks

ok just for the hell of it I replaced the 10 amp fuse this morning again and made sure the relay above it was sitting in tight. I hit the ac button and the ac worked perfectly. Hopefully it works this afternoon when its 100 out. Still confused to whats causing this. I thought the relay above it was for the heater fan. Anybody?:facepalm:

Wires to the compressor ok? I figure if the fuse is popping possible compressor issue, wire at the compressor shorting? I know on mine it has only 2 wires one goes directly to the ground and the other just to kick it on, might take a look see just to make sure just an idea also I'm not positive but if the compressor has some sort of issue maybe the extra load is causing that fuse to pop? Like I said not an expert here just throwing out some ideas for ya to look into:). Being from Texas I feel your pain on the suffering:( good luck maybe someone else will chime in here also to help a roasting member:)

Blowing a fuse is usually because of a short or too much load from a componant. Do you have a schematic to look at?

Maybe clutch coil going bad? Maybe the wire to the clutch is shorting? I have had blower motors die and not short. I wouldn't think a relay would short.

Keep us updated,

yeah theres one wire going to the compressor. I checked the voltage on it at first to make sure the compressor was getting power. ONce I saw that it wasnt I checked the fuse behind the glove box and found it was blown. I changed the fuse and it started working. But now Im sure it'll blow again soon. Thanks for the help. Its no joke here in texas. My last toyota didnt have ac. It was annoying showing up everywhere all sweaty. AC is a must down here.

Well that's creepy:) I like your thinking at the same time.

Ill check the compressor after work. Its pretty grimey in there. all the other post I read about the ac were regarding the blower fan not working. My fan works perfect. This is the original compressor on the runner though, it blows cold as ice though.

I'm in AZ so I know what it's like without A/C. Getting a schematic will save you a lot of time.

Not sure why what I said is creepy?

I refreshed and looked at your post and its almost a duplicate of my post replying at the same time, but I think everything is creepy:)

ok so the fuse keeps blowing, checked all the wiring. I was wondering if the fuse would blow if it is low on r12?

Check out this diagram from 95...yours maybe a little different.
It seems the fuse comes before anything else that has to do with AC...even the switch.
I'd check the switch to see if there's a short first. You might be able to just pop it out.
Attachment 160826

It doesn't look like it.

If the low pressure switch is open, then no power will come from the amplifier, and the AC should simply not come on.

I suggest trying to rule out the compressor itself. Either it is the compressor...or one of the many other wires, switches, relays, gremlins, etc...

With the truck off and the wire disconnected, Ohm out the AC compressor (clutch contact). One probe on the wire connection, second on a ground, amp meter set to Ohms. I would expect (this is an (un)educated guess) around 3-50 Ohms, no more than 100. The true failure would be for the ohm meter to indicate infinity (usually indicated as (1,000 or OL)). This would also be observed if you set the meter to chime on continuity, and it indicated continuity from the wire contact to ground. If continuity is indicated, the motor winding has come loose and you either need it re-wound or replaced.

If this checks out, then I would Isolate the motor with a direct signal and check the amperage. If it is a 10 amp fuse blowing, then the compressor should never get above 10A. Disconnect the wire from the compressor, and run a power wire directly from the positive on the battery to the clutch contact. I would probably run one wire from the battery and one from the compressor. Then start the truck, touch the wires together and check amperage with a DC amp clamp. Do this while revving the motor up to 3500 rpm. If the amperage ever spikes above 10A, then the problem is the compressor...If the amperage stays below 9A, then start on the gremlins, but at least you will know it is not the compressor.


Oh yeah...it's hot in Florida too...I'd drive a truck with no windshield before no AC...cause then you wouldn't need AC (that should be your last resort)...

Edit:

After thinking about this...I thought I should put a caution in there...when performing the Amp test, you need to be quick with getting the amp clamp on after engaging the compressor, and you need to be ready to disconnect the circuit quickly. Once the connection is made get the amp clamp on there immediately...proceed with the test, but the minute you see Amperage greater than 10...Stop! You can do it again after a period of rest, but you don't want to give that direct amperage to the compressor for long if it is exceeding design amperage. Since you are going to be running an un-fused connection, if there is a major problem in the compressor it could catch fire. I would not expect the problem to be that serious since it is only occasionally blowing the fuse, but definitely something to be aware of.