The Stovebolt Site Forums The Shop Area The Electrical Bay Testing Heater Motor

I have a 51 Chevy 1/2ton with the original 6V electrical sysem. It currently has an old (dare I say it) Mopar heater in it. I recently came into a fresh air heater out of a 49 Suburban that, I am told, has a good core. The motor has two wires coming off it; I believe one is the ground that hooks back onto the metal heater casement and the other is just a black lead. How can I safely test the motor?

Concerning installation, in looking at a couple of parts catalogs (LMC in particular), I see that there are a number of different parts available, such as "heater resistor," and "heater valves" (both 5/8" and 3/4"). Can someone give me some glues as to what I need for the installation and any tips on the installtion itself? Besides the heater unit (and I'm thankful to have that), the only other item I was given was a cable lead and handle that says "Defroster."

"Thanks" in advance for your advice.

just touch the 2 wires to the battery posts - case wire [ground] to neg, red to pos

the 'heater resistor' is either for running a 6V fan motor off 12V, or the control that gives you low and fast speeds - the 'valve' is the thingie that goes in the water line to control/stop the water flow to the core

Kieth's manual page has the 51 accessory manual w/ heater info

Bill

Bill - Thanks for the input and parts reference.

Q.: If, in fact, the unit I have is out of a 49 Suburban (as I was told), was that motor designed to run on two speeds, or are all the heater motors designed to run on more than one speed? And did the 51 Chevy 1/2ton have a multiple speed motor as original equipment?

Q: From what you indicated, I believe you are saying that the resistor is needed only if I set it up to run on two speeds. Correct? If so, does it follow that I would not need the resistor if I decide to just run it at one speed?

Final Q. Do you know of any printed mateial out there that would give me the circuitry schematic for the heater and other accessories for my 51?

Thanks again. Oh ya, do you know where I can find an original On/Off switch for the heater fan, or is that like finding hen's teeth?

KenZ

Ken - the motors are all speed controlled by a variable resistance in the switch, which is available from any vendor - a regular on-off toggle will do it if you prefer to run only full speed, but I think you'd be happier having the speed control

the shop manual should have the only schematic you need - check Kieths list for any that might help - any acessories not shown on the main electrical diagram just get one hot wire from a fuse panel, other side to ground - like the heater would have the red wire to the switch, and the switch to some power point supplied by the ignition sw, with an inline fuse - case wire to the dash or firewall

Bill

Bill - Thanks. I'll be sure to keep an eye out for the 51 manual you are putting together. Good luck in your work and stay safe.

Bill - Followup to earlier message. I misunderstood what I read when I opened the attachments you placed in your postings. It is Kieth that is putting together the manual for the 51, not you. And the posting about the "51 accessory manual" you posted to your first response practically gives every detail of the installation I would need.....so I'm in good shape. Thank you.

Kenz, If youir motor is a 6volt motor and you now have 12 Volt system in your truck you do need the resistor or you will burn the motor up or the truck if you do not properly fuse the heater wiring.

Jim

cujo - I should be OK. I'm still working with the original 6V system. Thanks for the heads up though. With the weather breaking here in the northeast, I hope to be able to start working on the truck again in the next week or two. Putting in the heater is "task No. 1" for this year, so I'll keep ya posted on the progress. Besides, I'm sure I'll have more questions before all is said and done and I couldn't do this stuff without the Bolters being there for info. Thanks again..