Air Conditioning Problems

[osucool]

Hi guys, Well, I have been reading through some of the other discussions on A/C problems and I think I have one that is fairly original.

I recently bought a second SC400, a 92, since I like my 95 so well and I really got it for a steal - I think.

During the test drive all seemed to work great including the air conditioning. That changed on the way home where I had a blinking light all the way.

The problem seems intermittent which is strange. I called a friend in the home A/C business to charge the system (R-12) and it seemed to take a little but the high pressure side is well above the pressure limits (I saw it reach 300 on his gauges). Just for reference the sight glass is pretty bubbly and there is a sticker saying that someone has used a UV flourescent dye to check for leaks.

Since there was a code that the system was flashing when hitting the magic "auto and recirc buttons" I wanted to clear up the electronics first before we blew something up.

The car originally was registering 43 as a code but when pulling the DOME fuse this reset and was cleared. I now get 00 or 21 depending on the time of day This is apparently normal due to the solar sensor voltage I believe.

Right now it is a roll of the dice whether the compressor will kick on and the system will work fine for a few minutes or the blinking will begin immediately at start up. I might be crazy but it seems to start working sometimes when I press the auto button and the AC "ON" buttons at the same time. I find myself driving down the road and trying different combinations on the A/C control panel. Everything seems to work on the panel

I ordered the Shop Manual on CD today at ebay but there is nothing like personal experience.

If anyone has an opinion I would appreciate the help.

Marty Holzer

[SKperformance]

well if you have bubles in the lens then you know there is definatly a problem

the light blinks only for when the ac compressor senses compressor lock up

not any other codes

you may need to find the reason for the bubles

it may just have air in it

pressing the auto button is just going to make it worse

so i would say stop doing it

as the system senses a problem and you are pressing it again and it may not sense as much pressure and let it turn on now

the last thing you want is to be driving and get the system to lock and the clutch for it which might burn a belt and leave you a few hundred dollars shorter never mind stuck at the side of the raod

just a thought

[osucool]

I believe I have things fixed.

When I was properly motivated this weekend to crawl under the car go over the wiring with a fine tooth comb I came across what I believe is the root of the problem.

There are two wires that come from the compressor pulley area that hug the case of the compressor as they make their way around.

I found a rip (or burn)? in outer insulation sleeving that I believe was shorting one of these wires to the compressor itself.

Upon pulling the wire back from the casing the problem with the A/C light blinking seems to have went away and the system seems to function.

I believe the system may be low on refrigerant which is the sight glass bubbles.

It is cool enough though for now.

I will keep everyone informed incase something changes.

[SKperformance]

good going

sounds like the wire for the compressor lock up being grounded out and causing the system to go offline

[FemiBoanerges]

I believe I have things fixed.

When I was properly motivated this weekend to crawl under the car go over the wiring with a fine tooth comb I came across what I believe is the root of the problem.

There are two wires that come from the compressor pulley area that hug the case of the compressor as they make their way around.

I found a rip (or burn)? in outer insulation sleeving that I believe was shorting one of these wires to the compressor itself.

Upon pulling the wire back from the casing the problem with the A/C light blinking seems to have went away and the system seems to function.

I believe the system may be low on refrigerant which is the sight glass bubbles.

It is cool enough though for now.

I will keep everyone informed incase something changes.

I have just bought a 1991 LS400 and have exactly the same problem that you had i.e. intermittently blinking aircon lights then the lights would stay on and the system would work perfectly but might cut out after one hour and come back on again. There is no rhythm or pattern to it. I opened the bonnet today and had a quick look to find the compressor. There are two short wires coming from the compressor that lie on its casing. Are these the wires that you pulled back from the casing? I will give mine a try. Have you had any further problems since that time?

Femi

[osucool]

Over the past few years this problem has come a back few times. Each time I mess with the wires and everything is fixed.

The probem I now realize is corrosion on the wire connector....The ring connector that attaches the one wire to the compressor body.

I believe this wire is the ground path and not making good connections. Upon cleaning the connector and the bracket and re-install this fixes everything.

Hopefully this will further help other folks with similar issues down the road.

Do this before replacing your compressor.

[agridi57]

Over the past few years this problem has come a back few times. Each time I mess with the wires and everything is fixed.

The probem I now realize is corrosion on the wire connector....The ring connector that attaches the one wire to the compressor body.

I believe this wire is the ground path and not making good connections. Upon cleaning the connector and the bracket and re-install this fixes everything.

Hopefully this will further help other folks with similar issues down the road.

Do this before replacing your compressor.

osucool,

I think I may have the same problem. I have a 96 SC400 with 180,000 miles. The A/C stopped working last summer. I took the car to the dealer and they told me that the compressor is stuck and the whole job will cost $3000 - $4000. I politely said that I could not afford the cost for the repair and left. As I was driving home, the A/C suddenly kicked on and worked fine for the next 3 summer months. However, the problem reappeared after not driving the car for a month in late August.

My question is can you see the connectors/wires from the top or do you have to get under the car to see them. Any pics by any chance showing what to look for?

Thanks in advance

[osucool]

The wire(s) are viewable from the top.....they are the ones that you can see that seem to drift off into the compressor pulley.

One of these wires comes out and is grounded to the Black painted bracket with philips head screw. Two screws are used to attach the bracket to the compressor.

To remove these two screws You will probably need to release the cable clip as I think it clips into the bracket, from memory.

Clean the connection points between this wire connector and the bracket and between this bracket and the compressor.

Re-install the two philips head screws and reclip the cable run.

Hopefully this works for you (or someone) as well.

[agridi57]

The wire(s) are viewable from the top.....they are the ones that you can see that seem to drift off into the compressor pulley.

One of these wires comes out and is grounded to the Black painted bracket with philips head screw. Two screws are used to attach the bracket to the compressor.

To remove these two screws You will probably need to release the cable clip as I think it clips into the bracket, from memory.

Clean the connection points between this wire connector and the bracket and between this bracket and the compressor.

Re-install the two philips head screws and reclip the cable run.

Hopefully this works for you (or someone) as well.

Thanks osucool.