A/C and Cruise
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
A/C and Cruise
So picked up my 87 today and I already knew it had A/C issues. The panel itself I can adjust the temp but it only blows hot. I can't turn it off or switch to Bi-Lev or anything else. Cruise doesn't work either. I am wondering what needs to be examined. I read about cleaning the contacts and and some other vacuum lines but am unsure as to where to start?
Other than that, mechanically the car runs great. The 4+3 is smooth and the engine runs strong. No knocks or anything else.
Other than that, mechanically the car runs great. The 4+3 is smooth and the engine runs strong. No knocks or anything else.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
you need to find the vac lines under the hood and make sure they are ok. If 2 things are dead, that screams broken vac line...either at the firewall entering the cabin OR under the hood....somewhere. Locate and trace each to the failed systems. Cruise is easy...I think you will find the broken fitting behind the distributer or the line to it off the plenum. No vac...no a/c controls (vents) and no cruise.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
The unit has a digital display with the temperature with auto capability. Hitting cold drops the number down and vice versa. I was hoping I didn't have to replace that whole unit. Going to take a look at the vacuum lines today when I get off work.
I guess the good news is, heat blows out no matter what temp is set, so winter here in Texas will be fine (supposed to be a bit rough this year)if I can't get it fixed in time.
I guess the good news is, heat blows out no matter what temp is set, so winter here in Texas will be fine (supposed to be a bit rough this year)if I can't get it fixed in time.
Team Owner
Joined: Jan 2003
Posts: 20,322
Likes: 249
From: Summerland B.C. Canada
These pages from my 86 service manual should help.
http://members.shaw.ca/dankai/Cruise%20Control%209C.pdf
http://members.shaw.ca/dankai/Cruise%20Control.pdf
http://members.shaw.ca/dankai/HVAV'S.pdf
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
Here is a good post on the HVAC controller
http://forums.corvetteforum.com/1568603057-post3.html
http://members.shaw.ca/dankai/Cruise%20Control%209C.pdf
http://members.shaw.ca/dankai/Cruise%20Control.pdf
http://members.shaw.ca/dankai/HVAV'S.pdf
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
Here is a good post on the HVAC controller
http://forums.corvetteforum.com/1568603057-post3.html
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
This will be a fun little project for me. The most I usually do on vehicles is replace liquids, batteries, tires, and drop exhausts. Not to savvy in this department but now that I have a car that I can actually work on I can learn some things. Thanks for the links, they will prove useful in my adventure.
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Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
Ok, haven't got around to repairing the unit based off advice here due to crappy weather and I need my whole garage. My C6 shares the garage and isn't going outside so it has to wait. But, I do have a video of what is going on. I can get the fan speed to adjust and can feel the air blowing out harder as I increase the speed but it takes a few button presses to get the fan to adjust either way. Below is a video of what is going on with the rest of the unit.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
Tomorrow is supposed to be nice between storms here in Central Texas so I will be pulling fuses, checking vacuum lines, and swapping out bulbs and relays. Hopefully I can let yall know what I find out on this and a few other issues im having.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Look for the vacuum check valve next to the distributor on the driver's side. It supplies vacuum to the HVAC system and the cruise control. It's probably bad. $4 part at any auto parts store. It looks like this:
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
Ok I replaced the valve (what a ****) and noticed the lines are cracked a bit but not all the way through to leak. AC is still a no go but at this point I am wondering if it needs more Freon. My only thing is that he said it used to work and stopped recently which leads me to believe that it is fine. Can I put the R-134 stuff in this car or will that cause problems? While I was at it, I swapped out every fuse on the passenger side door area just to be sure as some where completely corroded.
Last edited by AAChaoshand; Oct 28, 2013 at 06:04 PM.
Drifting
Joined: Mar 2013
Posts: 1,952
Likes: 239
From: Venice Cali.
make sure the line from manifold goes to the cone part of the check valve
on the 2 nipple side one to heater doors and the other
Goes to a t splitter then 1line to cruise
And 1 line all the way to the ball up by headlight. If a break anywhere in thevacume
line your cruise and blend vents won't work.the ball thing is
Important tonot be cracked or anything.
Good luck
on the 2 nipple side one to heater doors and the other
Goes to a t splitter then 1line to cruise
And 1 line all the way to the ball up by headlight. If a break anywhere in thevacume
line your cruise and blend vents won't work.the ball thing is
Important tonot be cracked or anything.
Good luck
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
I will have to recheck the valve but as I pulled one line off I put it on the new one and went one by one so I am 90% certain I got it hooked up right. I will check again tomorrow. That thing is a complete pain in the *** to get to. If I am going to check and reseat if incorrect, I might as well get new vacuum lines that arn't all cracked and jacked. On a positive note, the buttons on the right for Bi-lev, econ, auto, and heater work now. I think it might have been a fuse with some corrosion as I said earlier. Getting the temp to blow right now is next.
My other task is to figure out what is up with the turn signals. 4 ways are fine but left blinks slow on front and back while the right doesn't blink at all. I have a replacement flasher I can install but need to wait on the book to find out where the unit is that needs replaced.
My other task is to figure out what is up with the turn signals. 4 ways are fine but left blinks slow on front and back while the right doesn't blink at all. I have a replacement flasher I can install but need to wait on the book to find out where the unit is that needs replaced.
Last edited by AAChaoshand; Oct 28, 2013 at 06:41 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
In the video I noticed several problems.
MANUAL fan up and down buttons: When you press those buttons the fan speed should show on the display. It goes from 01 up to 10. Also, when you press the AUTO button the LED over it should light and the display will show the current fan speed.
When you press the red WARM button the temperature should go up to a maximum of 90. The minimum is 60.
The EXT TEMP button will show the temperature reading from a sensor in front of the radiator on the passenger side. Is it really -12°?
My guess is that the car sat for a long time without being used and the contacts corroded. You need to take the HVAC control head apart and clean the contacts. The classic method is to use a pencil eraser and rub it on the pads on the PC board that the buttons touch. Test before putting it back together.
MANUAL fan up and down buttons: When you press those buttons the fan speed should show on the display. It goes from 01 up to 10. Also, when you press the AUTO button the LED over it should light and the display will show the current fan speed.
When you press the red WARM button the temperature should go up to a maximum of 90. The minimum is 60.
The EXT TEMP button will show the temperature reading from a sensor in front of the radiator on the passenger side. Is it really -12°?
My guess is that the car sat for a long time without being used and the contacts corroded. You need to take the HVAC control head apart and clean the contacts. The classic method is to use a pencil eraser and rub it on the pads on the PC board that the buttons touch. Test before putting it back together.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
Yeah, I figured that was going to be necessary. It wasn't -12 for sure, Central Texas here, if its that cold we are in big trouble. The manual fan up/down work but it takes quite the bit of pressing to get them done. So, I will see how to remove this unit and clean the contacts. I got a Haynes manual in the mail that is supposed to be here tomorrow. Even some of the fuses I swapped were corroded.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
Where the Fuse block connections corroded as well, if so these need to be cleaned.
Thread Starter
Instructor
Joined: Feb 2013
Posts: 155
Likes: 0
From: Central Texas Texas
From what I could see, the fuse box itself looked fine. As far as the R134 goes, I am not sure. Are there any obvious signs that it has been converted? Still new to the whole DIY thing at this level on older vehicles.