Hdmike444

So I am trying to figure out why I only have high on the blower motor. I replaced the resistor on the heater box and the plug to it as they were melted, still only have high. I thought I read that the resistor should be the problem, could it be the relay? Do the dash switches fail?

Sugar Bear

Yes the dash switches fail and dash switch connectors also melt/fail. Is the fuse good? Is there voltage to and through the fuse?

Good luck!!!

Hdmike444

I’ll check the fuse but if I have high then I’m assuming the fuse has power correct? What’s the best way to replace the heater fan switch? Or get to it to test?

Sugar Bear

The fuse for high speed is separate and inline vs. in the fuse box. High speed will work while lower speeds do not. As for the best access to the switch I’ll wait for others to chime in, it’s been awhile since doing that job. IIRC you have to remove a couple of small “fun to get to” screws from underneath/behind the dash.

Good luck!!!

Hdmike444

So the fuse marked heat/ ac has power to both sides. I replaced the blower relay, still only high. I’m searching through chassis service manual trying to find out how to diagnose, anyone know what else I should try. My guess is the switch is a nightmare to get out and or test in place?

Sugar Bear

The relay is for the high speed only, Yes you need to get at the switch to test it. I don't know how to access it.

Someone will chime in that does.

Good luck!!!

Hdmike444

So I got the switch out and jumped the wires in the plug to the switch and got the fan at different speeds depending on which wire I jumped so I’m assuming the switch is bad. I just ordered a new one so we will see.

Sugar Bear

You found it. Connections look ok at the switch? Not burned?

Hdmike444

No they look surprisingly good

RetroRanger

most of the switches in these cars are simple mechanical contacts. If you can open the switch up it likely you can repair it

Fun71

And you have nothing to lose if you open it and can't repair it.

Be sure to take pics and let us know how it goes if you take it apart.

Hdmike444

Ok so apparently it isn’t the switch, new switch same problem. To make things worse I shorted out the power to the switch while trying to test it. Now no power there at all and no blown fuses??? I’m thumbing through the manuals now but another question is should the power distribution box above the distributor cap have power with the key on, as now it does not. I’m not good with wiring and schematics at all.

Hdmike444

So it turns out I have a power issue from the fuse block. When I add power to the switch from another power source all works perfectly. Anyone have any ideas on how to add a new wire from the fuse block? Or can I use the spare power that I found behind the dash?

Hdmike444

Victory! Turns out the fuse holder was not making a good connection. I scraped it down a little but need to figure a good way to really clean it. Now on to vacuum lines