Passenger Side AC/Lack of

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
Hello!

Just got back from a trip to Rialto Beach/2nd, 3rd, etc and finally let someone else drive the Disco on the way back. Outside temps were about 80 and while sitting in the passenger seat, the upper AC vents were noticeably warmer and the foot vent blew hot air even when put on just the upper vents.

First thought was that since the heater core tubing is there, its excess heat from that but since the upper vents also were warmer im not so sure and leaning towards the actual dual zone passenger AC dial. While on the road, i opened the glove box and fiddled with the plastic pieces that move some of the vents around but couldn't get it to go cooler. i did get the floor vent to calm down a bit but the top vents were still warmer with AC blowing.

My questions are:
Is this normal for the passenger side to be warmer due to the heater core tubing?
Is there potentially a fault in the airflow on the passenger side?
If i were to completely bypass the heater core in summer time, what issues may arise?

The car itself is running cool for warmer weather (188-194, HW and idle).

Thanks!
 

Swedjen2

Well-known member
Sep 12, 2018
376
61
California
Since you live Seattle, how often do you run your A/C? 2 or 3 times a year? Unless you head over to Spokane.
Another site said the blend motor(s) are stuck or kaput. Cycle the hot and cold back and forth - that MAY unstick the culprit.
If not, it's off to Lamorna or Precision Autoworks for you. Unless you want to dig into your dash and screw around in there.
 

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
Since you live Seattle, how often do you run your A/C? 2 or 3 times a year? Unless you head over to Spokane.
Another site said the blend motor(s) are stuck or kaput. Cycle the hot and cold back and forth - that MAY unstick the culprit.
If not, it's off to Lamorna or Precision Autoworks for you. Unless you want to dig into your dash and screw around in there.
Honestly, the windows down works most of the time. The issue im running into mainly is that any air circulation, AC or not blows hot air out of the passanger footwell which can be uncomfortable.

Im not opposed to taking the center console out, ive done it before. It sounds like its more of a mecahnical vent issue behind the center console.

What issues would i run into if I bypass the heat core all together?
 

Swedjen2

Well-known member
Sep 12, 2018
376
61
California
What issues would i run into if I bypass the heat core all together?
I by-passed the heater core in the RRC for 9 months with no issues, until the onset of winter forced the issue.

I wondered why nobody made a manual, after-market heater core shut-off valve for early RRCs with that crappy vent and A/C
system.
If they'd brought over a couple of Volvo's heating and cooling engineers, the early RRCs would be worth another 10K. But No.

I've got a '90 Volvo 740 that still heats and cools just fine with no constantly leaking hot air cooking your right foot and legs.
I don't mind it from November thru early March, but that crap blows chunks in July and August.
 
Last edited:
A couple of D1 mates here have do this, using an electric Ford Fiesta valvle that cuts heater flow and does a bypass. As older 1994/RR heater panel do have a switch in each temperature selector knob(equipped but not connected), they used them as a paralell switch connecting water valvle when one of these temperature knobs is turned to increase temperature.
But, i didn't have issues with standard heater in 20 years, having very high temperatures in summer so didn't make this big work.
Regards
 

pdogg

Well-known member
Jul 18, 2005
1,196
20
Phoenix, AZ
is this a D2? possible blend door motor failure.. it happened to me with similar problems..

1 - Turn ignition OFF.
2 - On the climate control panel, press and hold both AUTO and Air Distribution buttons.
3 - While holding these buttons down, switch ignition ON to position 2.
4 - Keep holding the buttons for 4-5 beeps and let go. The fault code (FC) results will be shown on the right side of the screen.

After doing this check I had two fault codes that popped up on the screen; 21 & 22.
I did a Google search and found a list of the fault code descriptions:

00 - no faults
11 - in car temp sensor fault
12 - ambient sensor fault
13 - thermistor fault
14 - heater coolant sensor fault
*21 - left sunlight sensor fault - open or shorted
*22 - right sunlight sensor fault - open or shorted
31 - left servo motor
32 - right servo motor
33 - distribution servo motor


* you will get these faults in low light, best to perform test in full day light
 
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robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
is this a D2? possible blend door motor failure.. it happened to me with similar problems..

1 - Turn ignition OFF.
2 - On the climate control panel, press and hold both AUTO and Air Distribution buttons.
3 - While holding these buttons down, switch ignition ON to position 2.
4 - Keep holding the buttons for 4-5 beeps and let go. The fault code (FC) results will be shown on the right side of the screen.

After doing this check I had two fault codes that popped up on the screen; 21 & 22.
I did a Google search and found a list of the fault code descriptions:

00 - no faults
11 - in car temp sensor fault
12 - ambient sensor fault
13 - thermistor fault
14 - heater coolant sensor fault
*21 - left sunlight sensor fault - open or shorted
*22 - right sunlight sensor fault - open or shorted
31 - left servo motor
32 - right servo motor
33 - distribution servo motor


* you will get these faults in low light, best to perform test in full day light
This is incredibly detailed and helpful, unfortunately I have a D1 so no codes to be had. I’m running with windows open at the moment if I have passengers. I have been doing too much to the truck at the moment to warrant pulling the dash out. Want to suss our the fuel trim problem I’m having afyer the new injectors were added yesterday.
 

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
A couple of D1 mates here have do this, using an electric Ford Fiesta valvle that cuts heater flow and does a bypass. As older 1994/RR heater panel do have a switch in each temperature selector knob(equipped but not connected), they used them as a paralell switch connecting water valvle when one of these temperature knobs is turned to increase temperature.
But, i didn't have issues with standard heater in 20 years, having very high temperatures in summer so didn't make this big work.
Regards
Interesting, is there a write up of this? Does the 94/RR have the same controls as a D2 or D1?
 

pdogg

Well-known member
Jul 18, 2005
1,196
20
Phoenix, AZ
This is incredibly detailed and helpful, unfortunately I have a D1 so no codes to be had. I’m running with windows open at the moment if I have passengers. I have been doing too much to the truck at the moment to warrant pulling the dash out. Want to suss our the fuel trim problem I’m having afyer the new injectors were added yesterday.
the D1 is probably very similar. try to pull your glove box out, and examine the operation of all the servo motors that open and close your blend doors.. there's probably about 5 of them.. some on the driver's side also.. no need to yank the entire dash out, I don't image .
 

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
D1's blend doors are only manually operated trough cables coming from His and Hers adjust buttons, and main selector. These cables can be loose and you can check them at both sides of heater box. You have to open glovebox and fusebox caps to reach both areas

Regards
cables look tight. I just had that console off to check. Also look good behind the glove box. I see them all move/articulate to full extent when moved by knob and by hand.
 

robbyb20

Well-known member
Oct 2, 2019
70
12
Seattle
Try charging it at rpm. I think around 1500. Mine looked charged but it was doing the same thing. I checked everything until I finally figured it out
I can give this another shot. I believe I saw this mentioned on another forum and forgot to try. I will see if i can today.