1995 Softdash HVAC mystery.

[captainbaker]

Background: New AC condenser, dryer, HVAC switch panel (replaced today as a hail Mary), blower motor, fan speed capacitor, system charged to proper levels. The AC system worked 'OK' before I replaced all these components but wanted to freshen up things to get max performance. Now it works great.....but only out of one side.

Scenario: Blocked off the heater lines to rule out mixing valve. After all the above work and the block off, I got 3.3c (38f) temps out of the dash vents. I drove it around for a few days in bliss. I parked it at the airport for 2 weeks and when I came back It blew the main 30(?) amp under the bonnet. Replaced the fuse and now I have a problem.

I can get ice cold/ambient/warm air from the left side of the AC vents (USA spec drivers side). Turning the temp knob on the Right side (passenger) gets ambient/hot air, no cold air.

I ran a borescope down the dash vent supply and confirmed I have 2 blend doors moving on both sides (4 total) when the temp knobs are being turned.

From Rave: With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energized, applying battery voltage to the Left Maximum Cool Switch (X267). When the Left and Right Temperature Controls are turned to the maximum cool position, the Left Maximum Cool Switch (X267) and Right Maximum Cool Switch (X268) close. Battery voltage is now applied to the Water Valve (K206). The Water Valve (K206) closes and prevents heated engine coolant from entering the heater matrix. When one or both of the Temperature Controls are not in the maximum cool position, battery voltage is not applied to the Water Valve (K206). The valve then opens and allows heated engine coolant to enter the heater matrix.


This sounds like turning both knobs to max cold closes 2 mystery micro switches which applies voltage to a mixing valve, which I dont think my car has (mixing valve) EDIT...my car does not have a mixing valve verified by dealer.

So im officially stumped.

Any ideas would be most helpful. And first post!

[DoubleChevron]

Background: New AC condenser, dryer, HVAC switch panel (replaced today as a hail Mary), blower motor, fan speed capacitor, system charged to proper levels. The AC system worked 'OK' before I replaced all these components but wanted to freshen up things to get max performance. Now it works great.....but only out of one side.

Scenario: Blocked off the heater lines to rule out mixing valve. After all the above work and the block off, I got 3.3c (38f) temps out of the dash vents. I drove it around for a few days in bliss. I parked it at the airport for 2 weeks and when I came back It blew the main 30(?) amp under the bonnet. Replaced the fuse and now I have a problem.

I can get ice cold/ambient/warm air from the left side of the AC vents (USA spec drivers side). Turning the temp knob on the Right side (passenger) gets ambient/hot air, no cold air.

I ran a borescope down the dash vent supply and confirmed I have 2 blend doors moving on both sides (4 total) when the temp knobs are being turned.

From Rave: With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energized, applying battery voltage to the Left Maximum Cool Switch (X267). When the Left and Right Temperature Controls are turned to the maximum cool position, the Left Maximum Cool Switch (X267) and Right Maximum Cool Switch (X268) close. Battery voltage is now applied to the Water Valve (K206). The Water Valve (K206) closes and prevents heated engine coolant from entering the heater matrix. When one or both of the Temperature Controls are not in the maximum cool position, battery voltage is not applied to the Water Valve (K206). The valve then opens and allows heated engine coolant to enter the heater matrix.


This sounds like turning both knobs to max cold closes 2 mystery micro switches which applies voltage to a mixing valve, which I dont think my car has (mixing valve) EDIT...my car does not have a mixing valve verified by dealer.

So im officially stumped.

Any ideas would be most helpful. And first post!

unless there is two evaporators in the dash, it has to be the vents in the dash not working properly. the evaporator is cold .... the air comping out elsewhere is cold, so unless it has a twin evaporator system (how would you fit that under the dash) .... it has to be the mixer flaps inside the dash.

[Tins]

Any ideas would be most helpful. And first post!

Can't help you with any of that, but I can say :welcome:

Pics are always welcome as well.

[captainbaker]

unless there is two evaporators in the dash, it has to be the vents in the dash not working properly. the evaporator is cold .... the air comping out elsewhere is cold, so unless it has a twin evaporator system (how would you fit that under the dash) .... it has to be the mixer flaps inside the dash.


Process of elimination......I have to agree with you. After re-reading the RAVE manual, It has to be the internal temperature flap (#11) that is froze or stripped. As you know, the 95 is an odd duck. Hopefully I can access the flapper valve after removing the blower motor and housing as they are both on the ofending side.

[captainbaker]

Can't help you with any of that, but I can say :welcome:

Pics are always welcome as well.

Lets see if this works. This is the offender.

http://i.imgur.com/qGtc5F2b.jpg (https://imgur.com/qGtc5F2)

And this is all the hidden screw locations to take the fascia off of a Softdash RRC (not a professional artist):

http://i.imgur.com/QyZ3CiMl.jpg (https://imgur.com/QyZ3CiM)

[captainbaker]

Can't help you with any of that, but I can say :welcome:

Pics are always welcome as well.

Posted a few pics, but since im the new guy....they have to approved by a mod which is understandable.

[Mercguy]

Posted a few pics, but since im the new guy....they have to approved by a mod which is understandable.

give it time, the forum is like a series 1 sometimes and it takes a few attempts to get the old bus moving ;)

[captainbaker]

Fixed! I had the chance to fly with a new copilot who was a semi retired exotic repair shop owner. Naturally the conversation turned to cars on this long flight and I described my issue. He said that he has seen it before and its low freon (R134). I told him he was full of it but he stuck to his diagnosis and tried to bet me $100. He said he doesnt understand how or why it does that, but a symptom of low freon is the car will blow cold on one side only. He says that before he goes downt he road of bad flapper motors, flapper servos etc....he checks the freon levels first.

[Old Farang]

Fixed! I had the chance to fly with a new copilot who was a semi retired exotic repair shop owner. Naturally the conversation turned to cars on this long flight and I described my issue. He said that he has seen it before and its low freon (R134). I told him he was full of it but he stuck to his diagnosis and tried to bet me $100. He said he doesnt understand how or why it does that, but a symptom of low freon is the car will blow cold on one side only. He says that before he goes downt he road of bad flapper motors, flapper servos etc....he checks the freon levels first.
Where are the fridges when needed? [smilebigeye]
Low freon level will mean the evaporator super heat is not where it should be. In other words, there is not enough gas to "fill" all of the evap. The ducting is probably in 2 halves across the evap, so one half is not cooling the air flow.

[captainbaker]

Where are the fridges when needed? [smilebigeye]
Low freon level will mean the evaporator super heat is not where it should be. In other words, there is not enough gas to "fill" all of the evap. The ducting is probably in 2 halves across the evap, so one half is not cooling the air flow.

Makes sense. I bought a second hand heater matrix box to cannibalize parts if I needed to. Im going to open it up to see how the air flows inside of it just to satisfy my curiosity as the manual is lacking.