'74 Heater motor wires question

My 1970 has an intermediate tub on it. This year I picked up a heater assy. out of a 1974. Yesterday I installed it and now my question about the wires.
Coming out of the motor I have a Black wire and a Yellow wire. Is this a 2 speed motor? Do I need to ground the motor or is the Black wire the ground?
Any help would be great.:?

 

anyone?

 

Thinking its the ground.
Seems like I read somewhere not long ago those had a ground wire where as the later ones dont.

 

Thanks Jerry.

 

If the parts heep is still wired up I can check it for you.

 

I have two heater motors, one with one wire and one with two. The 2 wire one has two fan speeds. I checked mine with a battery charger. I hooked the neg. wire to the case and briefly touched the other wires to the pos. side (one at a time). It worked pretty good as a tester.

I used this method to test the wiper motor too.

Jim

 

The black wire is the ground for the motor.

 

You are right!
Last night I just went for it. One wire at a time I touched them to 12volts. Neither wire worked. Then I grounded the black wire and then touched the yellow wire......we have fan.

Thanks for all the imput.

 

Just an update. The proformance of the blower motor was very disappointing. I was searching for a better blower motor for the '74 set-up. While I had the blower motor / fan assy out of the jeep. I had it setting on the bench, I decided to hook it up to a power supply to see how fast the motor was spinning. It seemed to have good speed but was putting out little air. Then I noticed an arrow on the fan showing rotation direction. It was pointing in the opposite direction that my fan was turning. So I attached the orange wire to ground and the Black wire to positive........guess what I have good air flow. Who would of thought. Black is positive and Orange is ground. I am not sure maybe the fan isn't original or maybe this motor isn't original. What ever the reason....I have a good(better than I had) Blower assy.

 

In my 73 there is a yellow wire from the ignition switch leading to the fan switch, this wire has a 15 amp fuse in it. From the switch are red and orange wires(hi/lo) leading to fan motor. It also has a black wire grounding the fan motor.

 

in my '74 i replaced all the heater crap and nearly froze to death.... i am going with the "Mojave" when i get home from A-stan... dude, look at that option before you waste anymore money on a stock CJ heating system. there is a thread on ECJ5 about it....

 

I have a second heater now mounted between the front seats. The '74 heater under the dash is doing the defrosting. All in all working well. Heres a pic of my aux_heater.

 

i have hope that after i buy/install that mojave i wont need a 2nd heater. the CJ heater worked ok for me if the temp was 40 degress or higher... once i got into the mountians and it was below 30 and snowing i couldnt keep my windshield defrosted, ...and i thought my YJ heater was bad. R)

 

I would rather not have a second heater since it takes up more space. Maybe someday I'll get mojave heater.

 

i am a little mad at myself for not going with the mojave it in the first place... i bought new control cables, a new blower and a new heater core. guess i could post it all up and see if i can get $25 back out of it when i do the mojave install :twisted:

 

Do you have the original OEM style control cables on yours or did you use generic? I bought some replacement controls that are out there and am not 100% pleased with them. They work OK, but they are not exactly like the originals. I'd give you more then $25.00 for the cables.

 

here is where i got them... http://www.vintagejeepparts.com
i have all 3 new in the box, never installed. PM me and we can work out something. i am in A-stan now but i am sure my wife can find the box (its in the CJ) and mail to you.

Sorry about the thread jack :JEEP:

 

I PM'd you before I read this post. Just another thought, on your heater box there are 2 holes for the defrost hoses and IIRC Jeep only used one hose. Did you plug the other defrost hose outlet on your heater box? I have seen some that were not plugged. And by the way, THANKS for your service to our country, you sound like a great American to me. Stay safe.

 

Ya know I gotta make a comment here. 2pwrlftrs4u, I am not familiar with how you have your heater set up, but I think you are doing it a disservice. It was -2*F here last night and I took my 120lb dog for a ride in my Jeep. The windshield was not frosted over and it was toasty inside. The dog pants like crazy and can steam up almost any vehicle.

I have performed a few minor modifications though. I capped off one of the defrost ports and I run a wet-vac hose with a wide wet-vac nozzle as a defrost nozzle. I avoided the stock defrost channel because I saw that the channels in the cowl/windshield gasket divert air from the windshield. The hose/nozzle has a clip on it that attaches to the oh-crap handle. I can quickly pop it off and tuck it under the dash when I dont need it. Even with a Mojave heater you would have to this, or something similar, because it merely pumps out hot air. I also covered up the small (2"x3") hole near the drivers side foot vent and used a yj difuser instead of the stock one which diverts air to the tranny cane. I, like you, also replaced my heater core. I also have a 195* tstat. It takes about 5 minutes from dead cold to get heat. You may have a colder tstat installed. I had a 160* tstat last year and the Jeep just never seemed to get warm enough for me. Maybe thats the solution to your heater difficulties?

Karl

 

maybe i can try that... i was just frustrated because i was only home for 2 weeks and spent way too much time on that heating system for it to not work well... my tstat is also 195... my jeep usually runs right on that too. theair that comes out is warm but not enough going to the windshield like you said. thanks for the help.