Regarding Jim Lane's blower-motor relay up-grade :

Would it work to step up blower-motor voltage/speed by adding a relay-switched direct-from-the-HOT wire, spliced directly into the blower-motor wire at the motor, with the relay triggered by a seperate toggle-switch, independent of any factory switching functions.

Wired thus, the toggle could be activated to give the blower full power/speed on demand, without having to dis-mantle the dash.

Is this do-able; or am I missing something ??



Reason I am wondering is that this could be done as a temporary quickie-fix, until time allows doing it the right way.

Thanks.

 

why not use a rheostat instead of a toggle and have variable speed control??
since the motor is 12V, you could simply by-pass all the factory stuff and run straight from teh battery, to a rheo, to the +blower input.... wouldnt that solve it better?
even in your description, why use the realy at all?

 

I would think you could run a switch to a relay. I just did the relay trick like outlined in the sticky. I didn't have to take out the heater control. Just pulled the screws and could lift a little to get at the fan swtich. Then open the glove box all the way.(un-hook the stop) That is allows the wire to be ran underhood. I would say you could do it in about two hours. I did mine over a long lunch break.

 

that's exactly what i did last week and it works great

 

That's exactly what I wanted to know.

 

If you are saying connect the blower motor through a relay Term. #87 installed close to the motor, Term. #30 receiving its FUSED power from the battery and controlling the coil through a toggle switch.

Yes that would work, it will not look purdy but it would work, but I would only do it on a temporary basis.

Having to tear your dash apart gives you the opportunity to inspect the concealed wiring and make any repairs that you would not ordinarily see.

Quote:
why not use a rheostat instead of a toggle and have variable speed control??
since the motor is 12V, you could simply by-pass all the factory stuff and run straight from teh battery, to a rheo, to the +blower input.... wouldnt that solve it better?
even in your description, why use the realy at all?

To handle the 15-20 amperes that the motor consumes you would need a BIG rheostat probably around 100 watts. A rheostat would get HOT, as it has to dissipate the heat, you would probably melt your dash.

If you wanted to control the speed it would be best to use a PWM Pulse Width Modulation controller. I have one that will handle 75 amps continuous and the actual control is a small 5,000-ohm linear taper potentiometer.

Why use the relay at all??

Check out my latest upgrade.

Jim

https://www.dieseltruckresource.com/...=158400&page=4