• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

No Blower Motor at any speed.

SnowDrift

SnowDrift

Ultra Conservative. ULTRA!
Messages
3,263
Reaction score
4,314
Location
Central Ohio map dot
I posted this in the electrical section, but also realize it's specific to the model years/makes with the 6.5 ('95, in particular), so I'm posting here, too. The link to the other post is below in case someone needs to look through it in a future search.

My blower motor spins when I hook 12v directly to it. When I have the key on, I have 12 volt power to the purple power wire in the first 3 settings, but the 4th setting gives me no power. What is this pointing to? Is the relay the square box on top of the air box that I cannot see the connection unless I remove it and the bracket?

I also have power to the ground wire through all four settings, as well as power to ground when the relay is unplugged. Where does the ground wire attach to the inside of the cab? I tried to follow it, but it seems to go into a harness and is wrapped to where it can't be seen.



http://www.thetruckstop.us/forum/sh...or-amp-control-panel-still-no-fan-on-95-c2500
 
You're heading in the right direction with the relay. (no high speed)

The power at ground is certainly weird. Do you mean that the ground will complete the circuit? Do you get conductivity from the heater motor GND to body or BATT GND?
 
Unwrap that "can't" be seen connection 6" from the blower motor. Cut the burned and melted connector out. Remove the glove box for better access to this connection. Replace the high amp draw blower motor if this connection is bad.

I don't recall or care where the ground 'went' as I recommend a separate ground directly to the blower motor. Your ground may have burned up and the cause for all the problems. You can and should fix that, but, still recommend the extra ground wire to the blower motor. I never tracked it myself on mine...

Sounds like you may also have a high speed relay burned out. Test the relay first as the control heads in 1995 were junk and fail often in weird ways.
 
How do I test the relay?

I grounded the fan motor to the dash frame and now I have speeds 1, 2, and 3, but still no 4. I rarely, if ever run the fan on high and all of this happened at once the other day when I had it on high (4) for an extended period of time. I can make a new ground for the fan, but the thing that bothers me is that I still have a short some place and don't want to cause a future fire since there's still power on a wire that shouldn't have power. That was the main reason I wanted to find the termination point of the ground wire.

I'll unwrap it and see what I can see.
 
Last edited:
The black ground wire goes to the engine. There is a connector as, war wagon said,near the blower relay and ecm. It has a red wire[power for the whole a/c system] and the black ground wire. This connector is way too light for the load it carries and should be eliminated with butt splices.
The lower speeds on the blower go through the different resistors and high speed goes through the relay. The blower switch may be bad.
Check for power at the orange wire at the relay.If no power check wire going to control. If it is good the control is bad.
If there is power at the orange wire ,check for power in the red wire at the relay. If no power, check the wire for short[melted connector as mentioned] all the way to underhood fuse box 50 amp maxi-fuse.
If you have power at the red wire at the relay ,check The ground between the relay and ground. If that checks out then the relay is bad.
I had many weird things with my 95 LD. It all went back to the fried connector. There still was a connection but not good enough for high speed.
 
bk95td, I'll test the relay tomorrow the way you suggest here.

I ended up learning that all my grounds in the dash had power to them. The ground from the fan, the one from the little harness with the black and red wires on it and then four or so other little wires all converge right beside the ECM and are soldered together. I spliced into the ground wire for the fan and now can run everything properly with exception to the fan on 4 (high setting). I did, however, get the high setting briefly today but it's not functional now.

Just so I know before I go cutting wires - you're saying the connection, itself, is too light with the red and black wires in it, right? I can cut on both sides of the connector and splice the wires back together directly and that will be a good connection. If so, then I'll try to get on that tomorrow, too.

Thanks for the help, guys!
 
The contacts in the connector are too small to handle the load. My ground was allmelted inside. I couldn't get the connector apart because it was melted. Bobbie martin had the same problem and had posted it in his sub. build.
 
thanks. I know you were pretty clear the first time, but I am always really hesitant to jump at cutting wires. I appreciate you reiterating that point for me. I'll definately be looking at it tonight as soon as I have a chance.

I also noticed someone cut the connector out in that post by Bobbie Martin, as well, and it still burned up the connectors later on. Is there further information on that from anyone?

Secondarily, why did a fuse not blow since I had a short??
 
Last edited:
This connector lasts many years and then suddenly you have trouble with the high speed setting quitting. Wire gets hot and burns open the connector till it cools off and maybe contacts again. Pop the connector apart and look for melting. It may have melted toghether, but, you would see that.

Not a dead short. Just a sudden high resistance connection that isn't designed to get hot. Expensive components like to blow out first and protect the 10 cent fuse.

Gas in tank fuel pumps do the same thing on their way out sometimes - melt the connector near the top of the tank. So again if you have a bad, melted, connector your blower motor is sucking too much juice.
 
Here is the burned up connection I found last night after the suggestions made here. I'll make the repair tonight, hopefully. I'd have never thought to check this - there are no signs on the outside of this melting, but I had to take it apart with pliers.

DSC_0154.jpgDSC_0153.jpg
 
We have been down that road. Glad to help. I have also just patched that connection with crimp connectors and watched it burn up the connectors again. Better motor ground was then added and replaced motor. This is why a new blower motor is in your future. I suggest a delco unit as they are quieter than the noisy el-chirpo Chinese knock off parts. For one the delco armature has a twist to shut up the motor and provide better low end power from it. The $25.00 Chinese motor don't.
 
Blower motors are only made by AC Delco. There will never be another make in my fleet, no matter the cost - I'm firm on that and learned my lesson long ago.

This blower motor is still relatively new (AC Delco unit). I have, indeed, added a ground to the motor wire and it will stay, even after this melted connection is repaired. You can never have too many grounds, in my opinion. I have some connectors that can be take apart (round, blue butt connector type). I'll give those a shot, unless someone says it's a bad idea. I'm thinking, though, that I'd rather have it fail there, than somewhere up stream in the dash where I can't get at it. I think that would suck worse than another failed connection. It took 16 years to burn the first one up, so I will probably be safe.

Since you said that, TD, I think I'll repair this before I pick up a new relay. Maybe the original isn't bad, then, and this wire deal was the only thing that caused the failure. Could a relay failure be intermittent, or is it a pass/fail part?
 
Power on the blue wire on settings 1, 2, 3 and power on the orange wire on setting 4. No power at all on the red wire. Ground is still well grounded and no power through the grounds. Relay bad?
 
As I said in post #5, check the power from the maxi fuse in the underhood fuse box. Red should be hot in run[key on]
 
That fuse was good when I checked it the first time through. I'll check it again in case it went out once the high side of the fan came on that one time.
 
And, I'm back in business. Relay is, apparently, still good. I have all four fan speeds again, an additional ground on the fan, as well as a replaced set of connectors on the factory weak connection. Thanks, guys, for all your help on this!!
 
You must log in or register to reply here.
Back
Top