Fix for a 4-button climate switch

[BillGrissom]

I don't know if any A-bodies had 4 push-button electro-pneumatic climate switches, but I'm guessing some did. Even if you have a 5-button switch, this info may help.

My 65 Newport is a non-AC car, with a 4-button climate switch. I have never seen these for sale. My 69 Dart had factory AC and a 5-button climate switch, which you can still occasionally find (Standard Ignition Parts HS-100, Paddock PAD03776, NAPA Echlin HC 6400). These need replacing because "blower on high" tends to melt all switches in the circuit. My 65 Dart non-AC car has no pneumatic switch, just cable operated levers (simple, robust), so don't know if any Darts had a 4-button.

Anyway, while removing my Newport's heater box, I came across drawings I made decades ago how I rigged a 5-button switch to serve the 4-button need. I mounted the 5-button on a custom plate. This also documents the '69 Dart climate controls, which may help someone. Finally, note how I wired a relay in all cars so it takes the current for "blower high". In my '69 Dart, both the climate switch and the blower speed switch (L-M-H)melted. You can find pre-wired relay bases for the common 40A auto relays on ebay.

 

[RedFish]

Thank you for sharing this info.

 

[1960dart]

Hi, new forum member here

Anyways, this is the exact information i was looking for. I have a related question you may have the answer to.

I have a 1960 dart that has the 4 button controller. I have vachum to the controller but the buttons don't seem to want to move. Should they be stiff or does the vachum help them move in and out or do i need to lubricate this unit somehow.

As well my wiring is a little messed up as I have no power to the controller right now so the fan is not running. I doubt this has any bearing on the controller push buttons being very stiff but i have been wrong before. Could this condition be what you are referring to as melted by the blower on high?

 

[C130 Chief]

The 5 button switches were used well into the 90's and should be readily available.

 

[BillGrissom]

1960dart,

The vacuum doesn't help the buttons move. If they are hard to move or jammed, that is usually because heat in the electical side melted the plastic.

I recall using an 1/8" aluminum plate with a few tapped holes to mount the 5-button switch in place of the 4-button. Of course, if you can find a 4-button switch that is best. If so, let others know the source.

When I reconnected my Newport's vacuum lines last Dec, the defroster door didn't open correctly. I swapped the red and white lines on the actuator and it then worked. Don't recall if my drawing was wrong or mis-read it. Anyway, may take some fiddling. I press the "Rear Heat" button to get heat. It seems the "Heat" button doesn't do anything now. My Newport never had rear heat (special duct thru console in bucket seat cars?). Don't know how 4-button Dart switches are labelled, since my GT doesn't have climate buttons.

Install a 40A relay for the blower high position or your replacement switch will eventually fail. I suggest adding many relays. In my Dart GT, I am putting a "Power Distribution Center" box by the battery. That lets me use relays for head-lights, etc, with smaller wiring thru the firewall (all needs replacing anyway), plus replace the individual relays on the firewall (starter, horn) for a clean look. I got a PDC at PickNPull (Jeep 5.9L, I recall), though some pay hundreds for similar from Painless Wiring, etc.

 

[weldedrail]

Wish I saw these diagrams a few hours ago. Much easier to understand than the factory service manuals. I have my vaccume lines hooked up and the push buttons seem to work like they should, although with the AC not charged its hard to know for shure if all of it works. I tested all of this with the blower motor hotwired to the battery. My problem now is the fan switch for the blower motor does not operate the fan when turned on. I could hotwire it and use a relay but I would like to have it all operate the way it did factory. Anything I should check?

 

[BillGrissom]

You can apply full 12 V to the fan without hurting it. That is what happen on the "high" setting (or with the relay I added). On both my 65 Dart and 65 Newport, there are two wires to the fan - blk = ground, dk grn = positive, as in drawings above. Just find a decent source of 12 V under the dash and jumper it to the dk grn wire and connect the ground. If your fan doesn't turn it is either burned out or the wheel is jammed (which will soon burn it up with power applied). A multi-meter would help verify you are applying 12 V and to measure the current draw.

On my Newport the dk grn wire is a single spade connector that loops over the heater box and connects to a single spade on the resistor pack on the front of the box. I know because I just put the box back in today after replacing the heater core (fogging the windows, then drenched the carpet). On my Dart the heater box is currently out. I looked at it but the dk grn wire is currently dis-connected, but it has the same single space female connector, so I assume it goes to the front of the box also. I will need to replace it since a P.O. did a klutz fix with yellow wire and butt crimps. The original wire is hard and brittle.

 

[weldedrail]

I am thinking the blower motor resister is bad. I need to probe a few areas with a test light. If I end up hotwireing it I will use a relay. I had it hotwired with a relay when this car was my daily driver just to get defrost. I have replaced my push button vaccume controls with a new unit from Rock Auto. I am hell bent on restoring my AC/heat to original so I will keep trying.

 

[cudamark]

Hi, new forum member here

Anyways, this is the exact information i was looking for. I have a related question you may have the answer to.

I have a 1960 dart that has the 4 button controller. I have vachum to the controller but the buttons don't seem to want to move. Should they be stiff or does the vachum help them move in and out or do i need to lubricate this unit somehow.

As well my wiring is a little messed up as I have no power to the controller right now so the fan is not running. I doubt this has any bearing on the controller push buttons being very stiff but i have been wrong before. Could this condition be what you are referring to as melted by the blower on high?

Sometimes you can get them working by lubing it but it's rare that you can totally cure it by doing that. Usually you can gently push the desired button in at the same time you pull the depressed button out. If not, you'll have to pull the switch and replace it or have it repaired/rebuilt. As Bill mentioned, it's a good idea to run the fan motor through a relay. The fan motors draw a lot of juice (even when they were new they were on the edge of overloading the circuit) and after 30-40-50 years of wear and added resistance, they will easily melt switches and/or bulkhead connections.

 

[cudajim]

The resistors in your diagrams above don't show wattage ratings which I would think are really important when it comes to a high current usage as in the heater circuit.

 

[cudamark]

Those resistors are used to change the motor speed. Whether the medium speed is 400 RPM or 425 isn't all that important. It's more important that the motor is turning freely and not drawing any more juice than necessary. It's usually the "high" position that melts everything down.....not the lower speeds. If you run everything through a relay with heavy duty wire, that should take care of the problem.

 

[BillGrissom]

The resistors in your diagrams above don't show wattage ratings which I would think are really important when it comes to a high current usage as in the heater circuit.

True. The resistors are part of the factory design. They are in the air flow of the climate box. I recall they are just loops of wire. It might be hard to measure the resistance with a multi-meter since it increases as the temperature rises.

I have never had a blower resistor fail in an old Mopar. That is a problem in newer Mopars. It is common in vehicles with cabin air filters. When the filter gets clogged, the air flow drops and the "resistor pack" fails. The symptom is that the blower then only works in the high position. My 02 T&C has a transistor limiter instead of resistor pack (electronic auto-temp). When it fails, as mine did, the blower stays on high in all positions. That part costs $50.