Ugh... No Heat
12-20-2023, 08:30 PM
#1
Intermediate
Thread Starter
Ugh... No Heat
My '94 has been laid up for a few weeks. Originally she was sitting because I had the radio refurbished by Dr Don's. So by the time the radio was returned and I found time to install, it was a few weeks. Then the brake booster went, so it was ANOTHER few weeks between ordering the part and, again, finding time to install. But I got that done today, and was backing the car out of the garage to bleed the brakes. I figured I'd let the car warm up with the heat cranked, and have my wife sit inside a toasty car and pump while I went wheel to wheel.
But the inside never got warm and cozy. I made a quick trip around the corner for gas, but still no heat. Digital numbers were:
Coolant :217°
Oil: 206°
Outside Temp: 43°
I had the heater temp cranked all the way up to 90, the vent selector on upper/lower, and the fan at 10. Still no heat. The AC condenser seems to be working bc there's water pooling under the passenger side, as normal. Here's something funky: When I put the fan in AUTO, the blower stops. It should be up around 8 if I remember correctly, if I have the heat cranked and it's cold outside... But no, it shuts off immediately.
The only things I moved when doing the brake booster were the cruise control solenoid, the ECM, and I pulled out the master cylinder. I don't know if there are any vacuum lines associated with the heat/AC, but I suppose something could have cracked. It's 30 years old after all. In fact, I do hear what I THINK is a vacuum leak, but I can't tell... I might just be paranoid. It sounds like an exhaust leak but gentler, and rises and falls with RPM. Sounds like it's coming from the area I was working in, though.
So here's a video of that, even though It might be a separate issue... Once I have this sorted I'll have to check the cruise control.
But the inside never got warm and cozy. I made a quick trip around the corner for gas, but still no heat. Digital numbers were:
Coolant :217°
Oil: 206°
Outside Temp: 43°
I had the heater temp cranked all the way up to 90, the vent selector on upper/lower, and the fan at 10. Still no heat. The AC condenser seems to be working bc there's water pooling under the passenger side, as normal. Here's something funky: When I put the fan in AUTO, the blower stops. It should be up around 8 if I remember correctly, if I have the heat cranked and it's cold outside... But no, it shuts off immediately.
The only things I moved when doing the brake booster were the cruise control solenoid, the ECM, and I pulled out the master cylinder. I don't know if there are any vacuum lines associated with the heat/AC, but I suppose something could have cracked. It's 30 years old after all. In fact, I do hear what I THINK is a vacuum leak, but I can't tell... I might just be paranoid. It sounds like an exhaust leak but gentler, and rises and falls with RPM. Sounds like it's coming from the area I was working in, though.
So here's a video of that, even though It might be a separate issue... Once I have this sorted I'll have to check the cruise control.
12-21-2023, 11:41 AM
#2
Melting Slicks
There are vacuum lines associated with the HVAC system, but I think they only control what vents the air comes out of. You may have an issue with the blend door actuator. Try disconnecting the battery for a few minutes. When you reconnect it, listen in the passenger foot well for the actuator cycling the blend door. (I think it happens right away, or you might need to turn the key on.) If you don't hear anything, the actuator may have failed with the blend door stuck in the cold position. Obviously check the fuse for it before digging in.
12-21-2023, 07:21 PM
#3
Intermediate
Thread Starter
Fuses are good. I have the battery disconnected now, I’ll try to work on it in the morning.
I can select floor, vent, and defrost just fine so vacuum seems to be working. What’s throwing me off is why the blower turns off when I go to AUTO.
I can select floor, vent, and defrost just fine so vacuum seems to be working. What’s throwing me off is why the blower turns off when I go to AUTO.
12-22-2023, 10:20 AM
#4
Intermediate
Thread Starter
Ok, so some progress.
I backed the car out of the garage and fiddled with the controls, and I forget which button, I think it was the vent button, but the green LED above it started flashing. I ignored it for the time being, but I'll get to that in a sec.
The big think I noticed, other than still having no heat, was that the recirc wasn't working:
So I did a little digging into the flashing LED and found that it means the climate control has an error code stored. The code that was brought up is code 02 - Temperature Door Motor Circuit Fault.
So I guess my question now is two-fold: 1) Are the recirc doors and blend doors on a common circuit? And 2) is it possible I knocked something loose while either under the hood or under the dash in the vicinity of the brake booster?
EDIT:
I just went back out to poke around the AC Diagnostics a little more, and the recirc is working fine now. Not sure what that was about but it seems to be cleared up... for now...
Still getting error 02, though, and of course no heat. Some other parameters I pulled, not sure if it'll help, but can't hurt, right?
Parameter 2 - In-Car Temp Sensor: 180 [10 = HOT, 230 = COLD]
Parameter 3 - Outside Temp Sensor: 138 [10 = HOT, 230 = COLD]
Parameter 11 - Program Number: -155 (255) [00 = COLD, 255 = HOT]
Parameter 12 - Mix Number: 00 [255 = COLD, 00 = HOT]
Parameter 24 - Temp Door Position: 128 [00 = FULL HOT, 253 = FULL COLD] This value does not change, regardless of what temp I've selected.
Parameter 31 - Temp Door Travel Range: 120 [Range = 100 - 200]
Parameter 34 - Temp Door Position Requested: 00 [00 = FULL HOT, 253 = FULL COLD]
I backed the car out of the garage and fiddled with the controls, and I forget which button, I think it was the vent button, but the green LED above it started flashing. I ignored it for the time being, but I'll get to that in a sec.
The big think I noticed, other than still having no heat, was that the recirc wasn't working:
So I did a little digging into the flashing LED and found that it means the climate control has an error code stored. The code that was brought up is code 02 - Temperature Door Motor Circuit Fault.
So I guess my question now is two-fold: 1) Are the recirc doors and blend doors on a common circuit? And 2) is it possible I knocked something loose while either under the hood or under the dash in the vicinity of the brake booster?
EDIT:
I just went back out to poke around the AC Diagnostics a little more, and the recirc is working fine now. Not sure what that was about but it seems to be cleared up... for now...
Still getting error 02, though, and of course no heat. Some other parameters I pulled, not sure if it'll help, but can't hurt, right?
Parameter 2 - In-Car Temp Sensor: 180 [10 = HOT, 230 = COLD]
Parameter 3 - Outside Temp Sensor: 138 [10 = HOT, 230 = COLD]
Parameter 11 - Program Number: -155 (255) [00 = COLD, 255 = HOT]
Parameter 12 - Mix Number: 00 [255 = COLD, 00 = HOT]
Parameter 24 - Temp Door Position: 128 [00 = FULL HOT, 253 = FULL COLD] This value does not change, regardless of what temp I've selected.
Parameter 31 - Temp Door Travel Range: 120 [Range = 100 - 200]
Parameter 34 - Temp Door Position Requested: 00 [00 = FULL HOT, 253 = FULL COLD]
Last edited by Mitragorz; 12-22-2023 at 11:01 AM.
12-24-2023, 12:04 PM
#5
so it seems your vent selection is working…but you dont have the ability to get heat.
ive never done a 90-96 but just fid my 89 with a full restoration of the hvac. nothing was working. im fairly confident that the basic diagnosis ports from the 86-89 to your late car system.
https://batee.com/products/90-96-c68...estoration-kit
most likelt the two “power resistors “ and/or their solder has failed. these resisters control the electrical signal sent to the TEMPERATURE control valve (door).
you can drop the passenger footwell cover and attempt to get power to the motor to verify it works…thats what i did…after that i went to the c68 programmer module to verify continuity on two wires from the module to the motor an they were goo. from there i repaired the solder connections and it was fixed.
im glossing over a hundred other things i did but thats what it boils down to.
the head unit sends signal to the programmer, which causes either the vacuum actuators to move vent ducting doors to move or/and the heat/cold door to move. sounds like the heat/cold door isnt moving.
ive never done a 90-96 but just fid my 89 with a full restoration of the hvac. nothing was working. im fairly confident that the basic diagnosis ports from the 86-89 to your late car system.
https://batee.com/products/90-96-c68...estoration-kit
most likelt the two “power resistors “ and/or their solder has failed. these resisters control the electrical signal sent to the TEMPERATURE control valve (door).
you can drop the passenger footwell cover and attempt to get power to the motor to verify it works…thats what i did…after that i went to the c68 programmer module to verify continuity on two wires from the module to the motor an they were goo. from there i repaired the solder connections and it was fixed.
im glossing over a hundred other things i did but thats what it boils down to.
the head unit sends signal to the programmer, which causes either the vacuum actuators to move vent ducting doors to move or/and the heat/cold door to move. sounds like the heat/cold door isnt moving.