a/c clutch will not engage

1991 supra guy · 07-12-2011, 09:12 PM

I have a 1991 6 cylinder 5 speed supra. The a/c light comes on but a/c clutch will not engage, can anyone help me troubleshoot? Also where can i get replacement shocks that hold the hood up? thanks

SilverMK3 · 07-12-2011, 09:59 PM

You can get replacement hood shocks at Autozone, Orielly, or Advanced Auto for about $40 for a pair. It's well worth it to keep the hood off of your head.

1991 supra guy · 07-12-2011, 10:04 PM

thanks I have visited Advance they do not have the hood shocks but do for the hatchback. I am looking for the hood shocks.

El Supracabras · 07-12-2011, 10:10 PM

First check to make sure there is refrigerant in the system. If there is not enough or none at all, the compressor clutch will not engage. If the system is full, it could be a bad pressure switch. These are easy to test by unplugging it and jumping the terminals to bypass the switch. There are other causes for your problem but those 2 are the most common and would be the easiest to check. Also if the car has not been retrofitted for R134A refrigerant (originally uses R12), you may have trouble getting it serviced at some shops.
I got hood lifts from Pep Boys for around $40 for both with 2 year warranty. Could probably find cheaper ones but the ones I bought appeared to be of decent quality.

SilverMK3 · 07-12-2011, 10:16 PM

Sorry, I thought that they had them at Advanced Auto Parts also. I bought mine at Orielly's, for $40 with a lifetime warranty. Try there.

1991 supra guy · 07-12-2011, 10:18 PM

Thanks, first should the freon be visible in the circular window going to cannister in front of radiator? If there is non does advance carry a retrofit for the new freon? Also we do not have a pepboys here in alabama. But i may try to get a pair shipped. Where is the plug to bypass connection into the ac compressor? Thanks

El Supracabras · 07-12-2011, 10:30 PM

No you will only see oil in there if the compressor is pumping. Retro fit kits are usually wherever the R134A is kept. Ask the counter person if you cant find them. You will also want to change the receiver/dryer (canister w/ window). There are 2 switches in the pipe going into the firewall just under the passenger side strut tower. I don't remember which is which but one controls the fan and the other is called a dual pressure switch (hi/lo), this one would cut out the compressor clutch if triggered by an incorrect pressure or if it was defective. Good luck.

Sonyps307 · 07-13-2011, 01:54 AM

Did Toyota switch to the r134a systems cause my 89 has the r134a fittings and not the r12 fitting. Unless The first owner did the refitting.

El Supracabras · 07-13-2011, 04:34 AM

I believe all cars sold in the U.S. after 1995 use R134A. Anything before that would originally use R12 with possibly very few exceptions.

speedfiend · 07-13-2011, 11:27 PM

There is also a fuse block in the passenger kick panel with a 10amp fuse in it.
That's where my a/c issue was...
If you had a bad pressure switch or amplifier the a/c light would flash.

07-12-2011, 09:12 PM	#1
1991 supra guy Stock Join Date: Jul 2011 Location: alabama Posts: 6	a/c clutch will not engage I have a 1991 6 cylinder 5 speed supra. The a/c light comes on but a/c clutch will not engage, can anyone help me troubleshoot? Also where can i get replacement shocks that hold the hood up? thanks

07-12-2011, 09:59 PM	#2
SilverMK3 Stock Join Date: Jan 2011 Location: Madison, AL Posts: 9	Hood Shocks You can get replacement hood shocks at Autozone, Orielly, or Advanced Auto for about $40 for a pair. It's well worth it to keep the hood off of your head.

07-12-2011, 10:16 PM	#5
SilverMK3 Stock Join Date: Jan 2011 Location: Madison, AL Posts: 9	Hood Shocks Sorry, I thought that they had them at Advanced Auto Parts also. I bought mine at Orielly's, for $40 with a lifetime warranty. Try there.

07-12-2011, 10:18 PM	#6
1991 supra guy Stock Join Date: Jul 2011 Location: alabama Posts: 6	a/c clutch Thanks, first should the freon be visible in the circular window going to cannister in front of radiator? If there is non does advance carry a retrofit for the new freon? Also we do not have a pepboys here in alabama. But i may try to get a pair shipped. Where is the plug to bypass connection into the ac compressor? Thanks

07-13-2011, 11:27 PM	#10
speedfiend Intake Join Date: Jul 2010 Location: Mobile, AL/ Iquitos, Peru Posts: 36	There is also a fuse block in the passenger kick panel with a 10amp fuse in it. That's where my a/c issue was... If you had a bad pressure switch or amplifier the a/c light would flash. __________________ 88 N/A targa, 5 speed, tint, thumpin' tunes, APEXi & KYB's, tweaked AFM, Hayden fan... *5 Favorite yodas I've owned, I am a believer!* 85 Supra 5 speed, tint, sunroof 77 Celica GT, 20R, 5 speed, tint, cam, header, tweaked Mikuni S/Ds, K&N 91 DX & 99 LE Camrys, for when I did the family thing 86 1 Ton P/U, 22RE, SR-5 speed, tint, buckets, 500w stereo, header, alloys, tweaked AFM, K&N 86 4x4, 22RE 5-speed, tint, 4" lift, cam, header, tweaked AFM, K&N, bored .040 500 character limit... Last edited by speedfiend; 07-14-2011 at 03:00 AM.

07-12-2011, 10:04 PM	#3
1991 supra guy Stock Join Date: Jul 2011 Location: alabama Posts: 6	thanks I have visited Advance they do not have the hood shocks but do for the hatchback. I am looking for the hood shocks.

07-12-2011, 10:10 PM	#4
El Supracabras 3" Exhaust Join Date: Feb 2010 Location: Chicago Posts: 240	First check to make sure there is refrigerant in the system. If there is not enough or none at all, the compressor clutch will not engage. If the system is full, it could be a bad pressure switch. These are easy to test by unplugging it and jumping the terminals to bypass the switch. There are other causes for your problem but those 2 are the most common and would be the easiest to check. Also if the car has not been retrofitted for R134A refrigerant (originally uses R12), you may have trouble getting it serviced at some shops. I got hood lifts from Pep Boys for around $40 for both with 2 year warranty. Could probably find cheaper ones but the ones I bought appeared to be of decent quality.

07-12-2011, 10:30 PM	#7
El Supracabras 3" Exhaust Join Date: Feb 2010 Location: Chicago Posts: 240	No you will only see oil in there if the compressor is pumping. Retro fit kits are usually wherever the R134A is kept. Ask the counter person if you cant find them. You will also want to change the receiver/dryer (canister w/ window). There are 2 switches in the pipe going into the firewall just under the passenger side strut tower. I don't remember which is which but one controls the fan and the other is called a dual pressure switch (hi/lo), this one would cut out the compressor clutch if triggered by an incorrect pressure or if it was defective. Good luck.

07-13-2011, 01:54 AM	#8
Sonyps307 Lexus & 550's Join Date: May 2010 Location: Baltimore Posts: 526	Did Toyota switch to the r134a systems cause my 89 has the r134a fittings and not the r12 fitting. Unless The first owner did the refitting.

07-13-2011, 04:34 AM	#9
El Supracabras 3" Exhaust Join Date: Feb 2010 Location: Chicago Posts: 240	I believe all cars sold in the U.S. after 1995 use R134A. Anything before that would originally use R12 with possibly very few exceptions.

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