No power to dash HVAC controller

[Ianmac]

Fuse is ok and have power on fuse terminal.
No power at the battery terminal (2) red wire power at ignition terminal (50) brown wire on the plug that goes into the back of the controller. Battery terminal should have power at all times.
I am having difficulty in finding a wire diagram and trying to trace where the red goes after disappearing into the wrapped loom and what else gets power from the fuse. I assume it also supplys the fan motor and the actuators in the heater unit I am not sure about if it suppys power to the a/c.
My suspicion is a broken or disconected wire between the fused suppy and the controller unit. Everything was running good then on my way home I noticed the unit wasn't lit.
I really dont want to take the dash apart and strip the wrapping on the loom unless I really have to.
Anyone have any ideas or knowledge of the route and connections on the way to the controller from the fuse?
Up until this occurred the only things are I disconnected the plug to the actuator that opens the door on the firewall it was grinding and not working I have another to go on but not done it yet also the A/C is very weak (due to the broken actuators) it's been like this about 2 years now with no problems.
Earlier in the week I thought I could smell burned plastic but had just passed some road work so guessed it was asphalt or something so perhaps something shorted and buned a wire?
No burned out fuses either.
Has anyone had any experience with this problem or know something I missed.


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[Ianmac]

Picture is of diagram of the plug at the back of the controller unit on the dashboard.

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[AK49BWL]

The red wire powers the blower fan and controller, and there is no "fuse" per-se, but a "fusible link" that your blower motor probably burned out by trying to suck too much juice. This will be at the power distribution block on the passenger side firewall. Now, don't ask me which one, because there are several up there... But I'm betting you won't have continuity from the dist block to the controller. You might get lucky and be able to see the link that burned out tho.

 

[Ianmac]

Ok thanks I will get my meter and check them out I was not sure if the heater used one of them.
The heater blower motor somtimes can be a bit noisy on startup for a few seconds especially if I dont use the truck for a few days.

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[AK49BWL]

That's a sign of worn out bearings, which puts a strain on the motor windings, causing high amperage draw. Now I'm certain the fusible link burned up lol.

 

[Ianmac]

That's a sign of worn out bearings, which puts a strain on the motor windings, causing high amperage draw. Now I'm certain the fusible link burned up lol.

At least its easy to get to on this truck I changed one out on my wifes old cavalier and had to perform some strange painful acrobatics.
Just about to check them links dodging the rain showers.

 

[Ianmac]

Found the culprit as soon as I took off the cover the fusable link was very corroded and it has actually burned the few strands left. I dont know how it had held up for as long as it did.

I am going to have to do a bit of digging into the harness to get to the connecter but still a easy fix.

The burned-out link is 14g and is the first on the left as you look from the front.

Thanks for your assistance I had totally forgotten about the fusable links. Haynes wire diagram aren't the best sometimes for problem solving.

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