A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette - ZR-1 Net Registry Forums

LilRedCorvette · 07-16-2019

I'm hoping to get a gut-check/some thoughts on how to diagnose some issues that may/may not be connected because I'm about to lose my ever-loving mind lol.

The car: 1994 non-ZR-1 A4 vette, 170K miles. In other words, at the age where all hell breaks loose via electrical gremlins and hard-to-find parts make maintaining a 25 year old car 'fun'.

A while back I had issues with power steering not working very smoothly, and subsequently replaced the PS pump. Seemed to work for a while, then it turned out I needed a new rack. That is all back in, including red-line PS fluid, worked fine. Fluid turned black again, so flushed/refilled that. It seems like it's working extra hard (possibly due to the issues noted below)?

Also a while back the a/c blew hot, ended up doing a recharge, worked fine for a while. Then the problem resurfaced with it being the clutch switch going out. Replaced that and the a/c worked again. Now it's out again. Refrigerant level is fine, replaced the switch again to see if maybe it was defective, nope, a/c still doesn't work. BTW evap core replaced several years ago (the first time I had a/c issues).

It also seems that the power steering works better if the HVAC is set to off. Otherwise, it's very rough turning the wheel. The a/c clutch also now appears to seize/hang up when the HVAC is on, so I've been keeping the HVAC off so that it doesn't, and also so that the PS works, just so that I can even drive it.

I tried pulling the C68 HVAC codes on the unit, but it comes up with exactly zero. Sent off my original HVAC controller a while back to batee.com to refurbish, which is also back in the car, but these same issues are present. I've noted that when I start the car, it defaults to HVAC on and 75 degrees setting (which I have to immediately turn off so that my PS works/a-c clutch doesn't seize up the serp belt), and displays rather 'wild' outside temps (for example, "127 degrees", which decreases over time).

I've also noted that my cruise control no longer works and have in my forum searches seen that cc & a/c issues can be related. The vacuum lines are pretty rough looking and could use a replacement...but have also seen that some sort of vacuum check valve can be an issue (?)

The commonality seems to be they are all accessories connected by the serp belt, so I am wondering if the a/c clutch seizing up would cause the other accessories to suffer...also, if replacing just the clutch would suffice vs the entire compressor? Or is this solely a vacuum problem? Or both??

Sorry for the novel, but just trying to cover all bases with what I have tried. I am not a mechanic, nor did I stay at a Holiday Inn last night, but I do try to systematically rule things out as I go.

Any thoughts or advice would be appreciated!

LilRedCorvette · 07-19-2019

UPDATE:

CC is working, found that my 5/32" hose was disconnected/dangling downward. Can't believe I missed that, I am an igit lol. Hoses do still need to be replaced but that is a big job for another time...will call this one a win for now.

Vacuum check valve OK, a/c related fuses OK. Took cell phone video of the clutch intermittently seizing up, so I *think* I have it narrowed to a/c clutch/related parts and/or compressor being the issue, but wondering if best to bite the bullet and replace all of those items...?

lfalzarano · 07-20-2019

The AC clutch switch is a cheap replacement. The compressor is expensive. Just had my switch replaced and have my AC back. 100 degree weather in NC is not fun to drive in A ZR-1!

Sent from my iPhone using ZR-1 Net Registry

LilRedCorvette · 07-20-2019

Quote:

Originally Posted by lfalzarano

The AC clutch switch is a cheap replacement. The compressor is expensive. Just had my switch replaced and have my AC back. 100 degree weather in NC is not fun to drive in A ZR-1!

Sent from my iPhone using ZR-1 Net Registry

As noted in my OP, already did that (twice)...

Quote:

Originally Posted by LilRedCorvette

Also a while back the a/c blew hot, ended up doing a recharge, worked fine for a while. Then the problem resurfaced with it being the clutch switch going out. Replaced that and the a/c worked again. Now it's out again. Refrigerant level is fine, replaced the switch again to see if maybe it was defective, nope, a/c still doesn't work.

I worked a bit more on it yesterday and think my issue is two-fold...

1. Vents not blowing any air. The compressor seems to be working just fine (lines are cold) with plenty of charge, and

2. A/C clutch itself getting hung up intermittently (took cell phone video, will try to post).

I'm going to pull the blower control module today and test for continuity...if it's bad, then there might be my vent problem. That's an easy fix.

A/C clutch/bearing/hub/coil/etc gonna be a bit more work to pull/test!

Any other thoughts on if I am/am not on the right track appreciated.

LilRedCorvette · 07-21-2019

Close to 98 degrees here today and spent the day in the garage working on this some more...because why not?!?!

Pulled and tested the blower control module for giggles and grins, it has continuity. Jumped pins and tested the blower motor itself, it runs fine also. Just at this point trying to rule out the easier stuff and move on to the harder items.

After reconnecting the car batt, I started up the car - while the a/c clutch was its unhappy self (hung up a bit w/horrible noise, but finally got going), I noted again the blower motor ran fine and then used the climate control to turn the temp down from what seems to be its default 75 degrees to 60 and put the fan speed up from what seems to be its default 0 to 10...and the a/c started to work/blew through the vents.

However, turning off the car and restarting, the a/c did not work again...nothing blowing from vents either but blower motor was indeed running just fine. It seems every time the car is restarted, the head unit defaults to auto - 75 degree temp setting with the fan speed on 0, and on the restart the outside temp is again showing really odd numbers (such as 127 degrees). Putting it back to 60 degrees and 10 fan speed via the head unit does not initiate the a/c to blow through the vents again.

It seems as though disconnecting the batt cleared some codes and I got a/c blowing through my vents, but I don't get anything at all on restarts. I've tried pulling diagnostic directly from the C68 head unit but that has yielded 0. Perhaps my head unit rebuild wasn't done correctly? Also have read something about 'blend doors sticking' but not sure about how that aspect works/need to investigate that a bit more...?

That, in addition to troubleshooting/testing the a/c clutch assembly for the hang-up/sound issue...not sure which component is actually bad (clutch/bearing/coil). It seems like either one or more of those parts is creating a parasitic draw on the power steering, making it difficult to turn when a/c is set to on (whereas the steering wheel turns just fine when climate control is off). The compressor itself is happy (when a/c is set to on, the lines are perfectly cold).

Has anyone ever (successfully) just replaced the entire clutch hub without disconnecting lines/discharging the freon/keeping the compressor on the car? If so, any tips/tricks? Or what new cuss words will I need to learn?

Any sage/'been-there' advice, please feel free to share.

LilRedCorvette · 08-14-2019

Just an update from spending time working the issue(s)...

Programmer rebuilt and back into the car, although on start-up it seems to still show 75 degrees and 0 fan speed (???)

New a/c clutch assembly also in. Schrader valve on the high side was leaking so that was replaced also. Everything seemed to be working but the blower motor (original to the car) is now doing so intermittently. A fist-bump to it a la The Fonz method seems to shock it back into working, but I'll be getting a new blower motor in there soon. Since the blower control module is original also, I'll throw a new one in for giggles and grins anyway while I'm at this project.

The outside temp still seems wonky despite the programmer and head unit rebuilds, so I think I'll see about a new outside temp sending unit as well.

Will see where this all goes...hopefully one day it will actually work as intended again!

07-16-2019	#1
LilRedCorvette Join Date: Dec 2012 Location: Virginia Posts: 99	A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette I'm hoping to get a gut-check/some thoughts on how to diagnose some issues that may/may not be connected because I'm about to lose my ever-loving mind lol. The car: 1994 non-ZR-1 A4 vette, 170K miles. In other words, at the age where all hell breaks loose via electrical gremlins and hard-to-find parts make maintaining a 25 year old car 'fun'. A while back I had issues with power steering not working very smoothly, and subsequently replaced the PS pump. Seemed to work for a while, then it turned out I needed a new rack. That is all back in, including red-line PS fluid, worked fine. Fluid turned black again, so flushed/refilled that. It seems like it's working extra hard (possibly due to the issues noted below)? Also a while back the a/c blew hot, ended up doing a recharge, worked fine for a while. Then the problem resurfaced with it being the clutch switch going out. Replaced that and the a/c worked again. Now it's out again. Refrigerant level is fine, replaced the switch again to see if maybe it was defective, nope, a/c still doesn't work. BTW evap core replaced several years ago (the first time I had a/c issues). It also seems that the power steering works better if the HVAC is set to off. Otherwise, it's very rough turning the wheel. The a/c clutch also now appears to seize/hang up when the HVAC is on, so I've been keeping the HVAC off so that it doesn't, and also so that the PS works, just so that I can even drive it. I tried pulling the C68 HVAC codes on the unit, but it comes up with exactly zero. Sent off my original HVAC controller a while back to batee.com to refurbish, which is also back in the car, but these same issues are present. I've noted that when I start the car, it defaults to HVAC on and 75 degrees setting (which I have to immediately turn off so that my PS works/a-c clutch doesn't seize up the serp belt), and displays rather 'wild' outside temps (for example, "127 degrees", which decreases over time). I've also noted that my cruise control no longer works and have in my forum searches seen that cc & a/c issues can be related. The vacuum lines are pretty rough looking and could use a replacement...but have also seen that some sort of vacuum check valve can be an issue (?) The commonality seems to be they are all accessories connected by the serp belt, so I am wondering if the a/c clutch seizing up would cause the other accessories to suffer...also, if replacing just the clutch would suffice vs the entire compressor? Or is this solely a vacuum problem? Or both?? Sorry for the novel, but just trying to cover all bases with what I have tried. I am not a mechanic, nor did I stay at a Holiday Inn last night, but I do try to systematically rule things out as I go. Any thoughts or advice would be appreciated! __________________ ZR-1/WAZOO 'Wanna-Be' 1994 Red Coupe - DD, Drag, Cruise 1989 Black Coupe - Circuit Track 2020 Black M240i Coupe - AutoX Last edited by LilRedCorvette; 07-16-2019 at 08:54 PM.

07-19-2019	#2
LilRedCorvette Join Date: Dec 2012 Location: Virginia Posts: 99	Re: A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette UPDATE: CC is working, found that my 5/32" hose was disconnected/dangling downward. Can't believe I missed that, I am an igit lol. Hoses do still need to be replaced but that is a big job for another time...will call this one a win for now. Vacuum check valve OK, a/c related fuses OK. Took cell phone video of the clutch intermittently seizing up, so I think I have it narrowed to a/c clutch/related parts and/or compressor being the issue, but wondering if best to bite the bullet and replace all of those items...?

07-20-2019	#3
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Re: A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette The AC clutch switch is a cheap replacement. The compressor is expensive. Just had my switch replaced and have my AC back. 100 degree weather in NC is not fun to drive in A ZR-1! Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]

07-21-2019	#5
LilRedCorvette Join Date: Dec 2012 Location: Virginia Posts: 99	Re: A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette Close to 98 degrees here today and spent the day in the garage working on this some more...because why not?!?! Pulled and tested the blower control module for giggles and grins, it has continuity. Jumped pins and tested the blower motor itself, it runs fine also. Just at this point trying to rule out the easier stuff and move on to the harder items. After reconnecting the car batt, I started up the car - while the a/c clutch was its unhappy self (hung up a bit w/horrible noise, but finally got going), I noted again the blower motor ran fine and then used the climate control to turn the temp down from what seems to be its default 75 degrees to 60 and put the fan speed up from what seems to be its default 0 to 10...and the a/c started to work/blew through the vents. However, turning off the car and restarting, the a/c did not work again...nothing blowing from vents either but blower motor was indeed running just fine. It seems every time the car is restarted, the head unit defaults to auto - 75 degree temp setting with the fan speed on 0, and on the restart the outside temp is again showing really odd numbers (such as 127 degrees). Putting it back to 60 degrees and 10 fan speed via the head unit does not initiate the a/c to blow through the vents again. It seems as though disconnecting the batt cleared some codes and I got a/c blowing through my vents, but I don't get anything at all on restarts. I've tried pulling diagnostic directly from the C68 head unit but that has yielded 0. Perhaps my head unit rebuild wasn't done correctly? Also have read something about 'blend doors sticking' but not sure about how that aspect works/need to investigate that a bit more...? That, in addition to troubleshooting/testing the a/c clutch assembly for the hang-up/sound issue...not sure which component is actually bad (clutch/bearing/coil). It seems like either one or more of those parts is creating a parasitic draw on the power steering, making it difficult to turn when a/c is set to on (whereas the steering wheel turns just fine when climate control is off). The compressor itself is happy (when a/c is set to on, the lines are perfectly cold). Has anyone ever (successfully) just replaced the entire clutch hub without disconnecting lines/discharging the freon/keeping the compressor on the car? If so, any tips/tricks? Or what new cuss words will I need to learn? Any sage/'been-there' advice, please feel free to share. Last edited by LilRedCorvette; 07-21-2019 at 10:47 PM.

08-14-2019	#6
LilRedCorvette Join Date: Dec 2012 Location: Virginia Posts: 99	Re: A-C/cruise/PS woes - 1994 non-ZR-1 A4 Vette Just an update from spending time working the issue(s)... Programmer rebuilt and back into the car, although on start-up it seems to still show 75 degrees and 0 fan speed (???) New a/c clutch assembly also in. Schrader valve on the high side was leaking so that was replaced also. Everything seemed to be working but the blower motor (original to the car) is now doing so intermittently. A fist-bump to it a la The Fonz method seems to shock it back into working, but I'll be getting a new blower motor in there soon. Since the blower control module is original also, I'll throw a new one in for giggles and grins anyway while I'm at this project. The outside temp still seems wonky despite the programmer and head unit rebuilds, so I think I'll see about a new outside temp sending unit as well. Will see where this all goes...hopefully one day it will actually work as intended again!