Yip, that would be my guess. cant help you on the diagnosis part of the head unit. i just sent mine in and had it rebuilt for the $75 and was done with it. im sure that there are a ton of little resistors and such in there along with a whole board. it could be the whole board that got fried, like mine was.

about the only other thing that could happen would be to have a short in a wire somewhere, i guess you could try to check power right at the outlet of the harness for the resistor that comes out of the back of the head unit. im not sure where that comes from or goes though, i didnt dive into it that far on mine. i just unplugged it and sent it off.

steve

 

Ok. Thanks. I am ordering one now. I am in Michigan and it is like 22 degrees where I am so I found one I can get quickly. Thanks again for the help. Hopefully this will fix it. I have checked pretty much everything else. It was working Sunday when I drove it then when I drove it today it quit. Must just be time.

 

There was also no burn electrical smell at any time either which would point to the control unit too. A shorted wire would generally have some smell from heat. I will find out when it gets here.

 

Ok so I have replaced the main three **** controller in the dash and I still have no power going to the resistor. Any other ideas as to the problem. I did pull the resistor and there is no melting but there is a slight dark discoloration on the left side of the connection on the resistor. Nothing on the male portion of the connection at all.

 

Ok so here is a list of items replaced and or checked.
Checked:
All blower related Fuses
All Blower Related Relays
Connections- any and all I can find related to the blower.

Replaced:
Main HVAC Controller in dash (three ***** main switch)
Hi Speed Blower Relay
Blower Resistor

I have power in one brown wire at the white connector where the blower motor wiring harness plugs in but when I plug it in I do not have power coming out of the same connection. I am thinking now maybe the harness but honestly am at my wits end with this thing. I Am heading out to pull the harness and test it with my DVOM to rule out broken wires or connection issues. Then from there I will be pulling the motor to test that if I cannot get a way to test it in place figured out.

I had blower then shut the truck off and when I got back in and took off I had nothing.

Any suggestions would be appreciated.

 

Update.
I have now removed the wiring harness that goes to the resistor - fan motor - high speed relay and tested continuity through all wires. I have voltage at the brown wire where the harness hooks into the main harness. When I plug the harness in without the relay, resistor, and motor being plugged in the power flows to the motor connector and the relay connector. If I plug the motor in I get power in the orange wire at the relay connector as well coming from what appears to be a return feed from the motor. If I plug in the high speed relay I loose all power to the motor and all the way back to the main connector where this short harness plugs in. WTF! I have replaced the resistor,the relay and the main switch. Could a shorted blower motor be causing this. Seems odd that the power goes away. I am wondering if the motor is shorted to ground or something?

 

Ok so I pulled the motor . I put power to it through the Ign. Voltage terminal and grounded the motor and it blows fine. It will also blow is I put ground to the other remaining terminal on the motor the High Speed terminal.
When I plug the harness in and plug into everything it gets power to one wire in the resistor connector. Power to the motor and power back to the relay atto terminals. If I plug in the resistor then there is no change in where I am getting the power. When I plug in the high speed relay it kills all power back to the connector.

I again have looked at al the fuses- relays and wiring. I have tested the blower motor. The continuity through the wiring harness. Replaced the high speed relay, the resistor (no sign of burnt connection) and the center switch assembly.

I am done for today as I am getting really close to pushing it off a cliff and its only just now up to 12 degrees here! Tomorrows plan is to start from the beginning again and look for something I may have missed.. If anyone has any suggestions I sure could use the help.

Thanks

 

sorry dude, i was out of town with no internet or anything from 2/10 till yesterday on vacation.

this is on your h3, so it is going to be different than my h2 most likely. I cant believe that you are having such trouble with it, even after replacing the head unit.

my blower motor is only a 2 wire i think, the resistor pack has 3 coming into it to control the speeds. a ground (full speed), digital ground (partial speed), and a power source which is 12v all the time.

it may be worth while to try to find a wiring diagram and see what they are supposed to be for power, ground, and colors. i honestly cant remember what colors they would be for sure unless it is listed in the previous posts.

I am pretty certain that the h3 is different wiring though. sorry i cant be of too much help any more. I got mine working and had some help from the guy that repaired the modules when i was going through mine looking for voltages.

steve

 

Thanks for getting back to me. I found a wiring diagram online and spent another 4 or 5 hours tracing and testing. Then found the issue to be corrosion causing a short at the fuse box under the hood. There was an hour during this time where it would work then not work. It was driving me nuts until I found the corrosion.

Thanks for your help

 

i ws on vacation snowmobiling actually LOL

thats a new one, so did you end up buying a new controller in the end? my apologizes on the money spent on it, hopefully it is in good shape and better than your other one. i would have put money on the fact that if you had power into it and not out, that was the problem.

it actually sounds like you didnt have power to it though, if there was corrosion at the fuse box. man thats a crappy deal, at least you got it fixed.

steve