Diagnosing heater that won't work

[Redmond49]

Hello,

 

The fan in the model 30 heater under the dash in my first series '49 doesn't work, and judging from the dust in it, hasn't worked in a while. I'm wondering if anybody would be willing to post some steps for testing to see where the point of failure is? I used a procedure in the service manual earlier this week to diagnose the horn that doesn't blow (appears to be the horn relay) but there is no similar process for the heater.

 

I did touch the two lines connected to the heater pull switch together while the ignition was on to see if bypassing the switch turned on the fan, but it did not.

 

 

Thanks for any help -

 

Ty

[Young Ed]

There probably isnt a step by step as there isn't much to the system. If you jumped it at the switch and got nothing I would then think you should pull the fan and try power right there. If still nothing bad fan. If it spins you've got bad wiring to the fan. I'm not familiar with model 30 is it one of the ones where the fan easily comes out the front?

[Don Coatney]

Do you have power to the switch? If you do then when the switch is turned on do you have power to the fan motor? If you have no power then investigate and find out why. If you do have power to the switch and power to the motor then remove the motor and repair or replace.

[Robert Horne]

The heater in my 38 Coupe sat in storage many years.

 

When I pulled it out of the storage box, the fan did not turn.

 

It was difficult to turn the fan blades by hand, but they would turn some.

 

After applying a few drops of oil, and turning some more, and more,

 

the fan became easier to turn.        I hooked a 6 volt battery charger to the

 

wiring, and it ran slow, but with a little more oil it ran good, and has ran good since.....

[greg g]

Mine also was fouled by dust and dirt.  Pulled the heater, removed the fan and motor and cleaned and put some penetrating oil on the fan shaft and allowed it to soak then manipulated the fan till it turned with little effort.  Followed up with some light graphite stuff like for speedo cables.  then I replaced the wire from the switch is it had had broken down and only about 6 strands of the the wire were still connected.  I uses 10 gauge wire soldered to the terminal on the heater motor.  I believe I had to use a small brass screw to effect a good contact to the motor, then soldered the new wire to the screw.  Also cleaned the ground attachment.  On the bench I ran the motor on 12 volts for few minutes in between several applications of the graphite lube.  You may also want to check the output of the heater switch as it operates through resistance.  The readings I got from mine were if I remember correctly, 3.4 volts at low speed, 4.7 at medium, and 5.9 at high speed. the other thing I usually do with mine when I use it is to start it by pulling it out to the high setting then pushing it back in to what ever setting I am going to use.  

Edited October 18, 2013 by greg g

[Redmond49]

Thanks for the ideas - planning to work on it this weekend.

[Redmond49]

To remove the heater, do I have to undo the firewall water hose connections from the engine side? I took the screws out from around the back edge of the heater housing inside the car to see if just the housing would come off so I could see the internals, but nothing budges. 

[Jerry Roberts]

Some of the heaters have nuts on the fire wall under the hood holding the heater in place . 

[Redmond49]

I think all I've got are the hose connections. And a strange little wire that is not connected to anything but that was tucked up into the heater on the interior side and that has a tiny loop on the engine side, not connected to anything. It goes through a tiny hole in the firewall.

Edited October 19, 2013 by Tyson

[greg g]

Assuming its a model 36 or similar, there are pressed steel nuts and a tapered fitting (to compensate for the angle of the toe board) behind the hoses. There should be the cable that operates the flap for the defroster ducts between the heater box and the pass side kick panel, and the two ducts themselves.   if you have access to compressed air you may want to try to blow as much coolant as you can from the assembly before you pull i away from the firewall. be sure to pull the top first and angle it to keep from spilling as you pull it out.

[Don Coatney]

I think all I've got are the hose connections. And a strange little wire that is not connected to anything but that was tucked up into the heater on the interior side and that has a tiny loop on the engine side, not connected to anything. It goes through a tiny hole in the firewall.

Is that mystery wire perhaps your defroster control cable that got jammed into the hose hole at sometime in the past? Or is it a heater water valve control cable that is no longer in use?

[greg g]

Does your system have the simple manual  open in the fall shut in the spring faucet type valve or does it have and adjustable one?

[Don Coatney]

Does your system have the simple manual  open in the fall shut in the spring faucet type valve or does it have and adjustable one?

Per the picture he posted it appears to be a manual valve.

[Redmond49]

I think it's got the manual valve that you open in the fall/close in the spring it's sitting there at the top-back of the motor right where the hose heads back to the firewall. The mystery wire must be a rigged solution to adjusting the valve from inside the car - the defroster cable was hooked up to the defroster diverter, although it was jammed in the cable housing and the connector bracket on the diverter was broken off it's rivet. 

[_shel_ny]

I think it's got the manual valve that you open in the fall/close in the spring it's sitting there at the top-back of the motor right where the hose heads back to the firewall. The mystery wire must be a rigged solution to adjusting the valve from inside the car -

 

It's possible that the valve on the head was replaced, and the cable was just left there. It may have been the cable operated type before. Connecting a cable to the manual valve would be less than effective. It would not provide sufficient travel to properly operate a manual valve in either direction.

Edited October 19, 2013 by shel_ny

[Don Coatney]

Shel, You changed your handle

[_shel_ny]

Shel, You changed your handle

 

Delivered the bizzy coupe to the new owner yesterday

[Don Coatney]

Delivered the bizzy coupe to the new owner yesterday

Sorry to see it go but I fully understand the "why".

[Redmond49]

Last night, I tested the heater by connecting the jumper cables directly to the wires for the heater motor to see if it would run, and it did not, so I read through all your replies and decided to go ahead and pull the heater. The water valve at the top rear of the block is stuck and I didn't want to torque really hard on it today for fear of breaking it - I'll save that for another day. So, I pulled the first hose off and as the coolant poured out I realized (too late) the radiator has quite a lot of capacity higher than the level of the hose, and it became clear very quickly that the valve was stuck OPEN. So I managed to shut the flow off pretty quickly by reattaching the hose. Happily, the drain cock on the front of the radiator was not frozen, so I drained the radiator and then was able to easily remove the heater without any water getting spilled inside the passenger compartment or under the car. 

 

So, now the heater is all in bits. It's a model 36, now that it's in the daylight I can actually read the model number. It looks like when the car was repainted with sparkly maroon paint, they did not pull the heater as it's back quarters seem to be wearing it's original beige paint.

 

Once I got it all apart and was able to spin the motor shaft by hand, I decided to try connecting it again to the battery. It runs perfectly fine!

 

I don't think the core has any leaks, but when I was messing with it some liquid seeped out from somewhere other than the two tubes, so I guess I'll take it to a radiator shop to have it tested and cleaned up.

 

@ gregg g: when you mentioned putting "penetrating oil" on the motor shaft, are you talking about WD-40?

 

Thanks, guys, for the info on this thread.

[Young Ed]

Ah model 36 now you're on it. Thats the base heater. Here's the one I redid for my 46 pickup.

 

[Redmond49]

Very nice! More questions now that I've had some time to ponder what's next:

 

1. I was just going to connect the longer hose from the front of the motor to the valve at the back of the motor for now so the coolant will still circulate. Do you guys see any problem with that, or should I cap the two coolant sources at the fittings?

 

2. Does the motor housing come apart? Greg mentioned he soldered new wires to the motor, but that connection is inside. I can see to get any movement when I try to twist or pull the motor housing. But it does look like there's a seam.

 

Tyson

Edited October 20, 2013 by Tyson

[Young Ed]

Either way will work and since you've got heater hoses already in place I'd go ahead and make the loop.

[greg g]

Can you post some pics of the heater you are working on.

[Redmond49]

Yes...here's some pictures of the unit and the motor. I pulled the switch from the car and connected the negative jumper from the battery to the ignition post on the heater switch, and connected the motor to the  motor post, and then connected the ground to the positive battery post. The switch works perfectly, both speeds.

 

So I'm thinking the problem is (or was):

 

- The wire from the ignition to the switch is bad. 

- The engine was just gummed up and required some turning to get it going again.

- Installed, the ground wire was screwed to the external metal case of the heater, metal to metal (no paint in that little spot). Is this perhaps not correct? The whole car is ground, but the heater might be insulated from ground due to how it's mounted. Maybe you guys can help me evaluate this one.

 

 

 

 

[greg g]

Your wires look to be in very good condition.  As i mentioned, one of mine was down to a half dozen strands and the insulation was broker right at the insulator where the wires enter the motor.  I needed to cut the wire off, then inserted a small bras screw basically into the center of the wire remaining going into the motor.  Then I soldered new wire to the screw and covered it with a glob of silicon to insulate it.  the screw went into the insulation and made good enough contact with the remainig wire to make a good circuit.

 

 I would run the ground to the firewall or some place on the dash board rather that to the heater body.

 

By the way rustoleum makes a hammered bronze paint that is pretty close to the way the heater was originally painted if you wnat to got that way while you have it out and apart.  The chrome band withthe model number come off fairly easily.