Heater question

[Timber]

I need to change out or maybe just clean the contacts on my heater/fan controls - as it is, the fan only works in the High position. Anyway, I do have limited but operative heat now. But running on High, it does not get to "run you out of there" heat. It does get comfortable, but Alabama winters are pretty mild - we seldom see temps below 20 F.

I'm pretty sure something needs cleaning that I don't know about. Any pointers are appreciated.

 

[wikallen]

do you own a multimeter?

 

[wikallen]

Check the switch with a multimeter first, then work your way out, or start at the motor first, and work your way back. Either way you should be able to figure out if it is wiring, switch, or fan

 

[Bethelfire]

On a 04 Jeep and a New Holland tractor it was the fan motor resistor that went out causing only high to work for me. Don't know if this is your problem or not but worth checking.

 

[Timber]

The heat works fine with the fan-speed on "high" but it never gets so hot that I have to turn it down. There's something wrong there that I can't pin point.

 

[DokWatson]

Like the other guy said, the resistor is cooked. As far as it not heating very efficiently, remove the glove compartment box and look at the cables that control the vent. They might need adjusting, the vent may not be opening all the way. Mine would get stuck between defrost and the regular setting.

 

[1986Blazerk5]

If its only working on high it HAS to be the resister, the high fan speed is the only speed that does not go thru the resister all the other speeds go tru that resister. I think it is attached to the blower motor under the dash. I could be a switch but 99% of the time its the resister. Good luck keep us posted

 

[ehuppert]

Resistor is located in the engine compartment, just inboard of the blower moter

 

[Timber]

Thanks for the heads-up, I'd planned on replacing the switch.

What heat I get is warm air. Even with the fan only working on High, it never gets too hot in there. I'll have to check the vent/blend door and make sure it's moving through it's full range of travel.

 

[pbrstreetgang]

I would like to know what you find out, mine is blowing warm, not hot like it used to. Up until the last two years, we didn't get that cold of a winter like we are experiecing now in KY.

 

[Seabee15]

ok I have a proble m maybe you guys can help. My blower comes on and off. When i start the truck, the blower works fine, but after a few minuts it goes out(all speeds go out), then a few minutes later it works(all speeds work)..

What could it be?

 

[rlwm211]

The resistor is connected to a splice that is in the harness where the power for high speed connect as well and they both connect to the fan. If the wire from the resistor has broken off, it could explain the non functioning lower speeds. I doubt seriously that the switch is bad since the high speed works. If the resistor is broken this could cause the problem. I have one if you need it. (you have to pull the resistor out of the plenum to see if it is ok)

The advice about checking your cables is spot on for making sure the blend door is swinging all the way to the warm side. You can easily see the cable operation when you have the glove box out. The other cable is the selector that routes the air to the floor, or the defroster.

Hope this helps

RL

 

[Grega]

As far as heat goes, is your engine getting up to full operating temp. like around 170 degrees. May need to check your thermostate.

 

[pistonium]

Another idea for not enough heat: after 20 or 30 years of collecting crud from the air intake and sucking in all the small parts, paper, pencils, etc. thrown on the dash, the ductwork and the actual coil of the heater generally benefit from a good cleaning. Also, I think there is a gasket on the door that determines heat output....a bad gasket makes the heater be 'on' to some extent all the time.

And FYI, I think the heating coil on these is always on, i.e. there is no valve in the water side, the only control is the heater door in the ductwork.

Good luck -

 

[rlwm211]

Absolutely correct on the constant flow of coolant through the heater core. Taking the heater apart to clean it is not an easy proposition. Even so, at some point it may be necessary. The foam you refer to is the gasket on the edges of the doors that seal the doors when you select heat, or not. The adhesive dries out and the foam deteriorates and can crumble off over time so that the blend door and the airflow select doors do not completely send the air in the desired direction.

I think one post about the actual operating temperature the engine is achieving is a good one and most all of these heater designs do not make much heat with the coolant below 160 and even then the heat output is marginal. When the coolant gets to 190 it starts making pretty good heat.

If you can read an electrical schematic, you can download the CUCV manuals at www.JATONKAM35s.com in the cucv tm download page. I cannot remember exactly which one it is in, but you should have all of them to properly maintain your rig. Besides, the other choice is to pay for the manuals as opposed to downloading them for free.

Hope this helps

RL

 

[pgwaldner]

Timber,
I just ran across your post here. If you need the switch or relay you can come get one off the red truck. BTW we have started our carpet project.

 

[camojcory]

I have been having a similiar problem with my heater as well. The difference is mine works on the high and the low setting, but not in the middle? So this wouldn't be the resistor would it? I will have to check the linkage in the dash as mentioned but it is @#$% cold out now and i don't have a heated shop to work in, so i might wait till it's a little warmer.

Also, how do you test to see what temp you are running at? My heater doesn't get real warm either, even on high. Maybe i should install a new thermostat to be on the safe side?

 

[Grega]

I installed an electric temp. gauge and an oil pressure gauge under the dash last winter. But I still kept the idiot lights. The temp this time of year in nebraska usually runs around 160 to 170. Diesels arent known to produce good heat in the winter, may have place cardboard over the grille. Also wrap your hand around each the the in and out hoses on the heater, they should be both feel the same temp. If not, the heater core is pluged. I replaced the heater core on my 67 chevy pickup last year because of low heat and it starting leaking. When I removed the housing, it was 3/4 full of debris, dirt, leaves, trash, etc. After replacing couldnt beleave the in heat differance.

 

[rlwm211]

As to the heat only on high and low, I would take the resistor out and check and I will bet that one of the elements has broken off of the resistor array.

Heater cores do get plugged internally, but I would imagine that these trucks never were allowed to have the coolant get weak, or the anti corrosive properties decline.

Diesels do make good heat, however, they have to be working to do it. Putting around town in your M1009 is not taxing the engine much. The thing to do is get a CUCV Winterfront and that will bring your temperatures closer to operating temperature.

YUou can get one from JATONKA or perhaps find one that is NOS, but they are rare.

RL

 

[hlcrkfrm]

Seabee15 ,My M1009 was doing the same thing it was the blower motor switch ,put in a new one and it works fine now. Dave