Hey gang...

is my memory on this correct?
does the heather lever/fan switch only have one electrical wire to it?

is that a ground wire or a current flowing wire?
(it must be hot since its identified in the current diagrams)

I'm trying to trouble shoot why my auxillary heater doesn't work and want to understand how that switch works.

when the switch is open/on.. does it send power to the engine compartment and regulator board? how does the switch work if it is only a single wire?

or does it then send a ground signal to the back instead?

thanks for everyone's time
brant

The lever connects the ground. The positive is in the engine compartment.

Ok...
then I definitely have a problem

when I put a test light on the single wire I get a faint glow, so there must be a feedback/short sending power down the wire.

when I connect a test light to the regulator panel on the forward pin (14pin) connector for the same wire (but with the connector off and just the panel pin). I also get a faint glow.

that must mean that my short is in the regulator board

but here is the weird thing. Either of the above 2 test light checks cause the fan to start running. So the faint ground I'm making must be enough to trip the relay?

someone please confirm if you would... I'm assuming that the faint glow/short I see with my test light is WRONG?

brant

I definately think that is wrong. Eliminate the fan lever switch and do the same check on the wire in the cockpit (removed from the lever). That can at least rule that portion out.

Everything is normal. When you put a test light on it, you are connecting the light from a wire that has power on it to a ground--so it glows. This lets enough current through that it "trips" the fan relay, which closes and sends power to the fan.

The way the switch works is: When you pull the lever all the way up, the switch grounds the wire that is plugged into it. This causes current to flow through the fan relay, which then sends power to the fan. So there is some power on that wire all the time--or possibly only while the ignition switch is on.

Sounds like you just have to plug the wire into your switch and it should work...

--DD

dave is right. that "ground" wire always has current on it!

putting a tester lamp on it will ground it out and make the fan run ...
Andy

Ok...
this is helpful.

Travis,
the faint glow I get from testing the single wire inside the cockpit is with the wire disconnected from the heater lever...

Andy, Dave,
thanks guys..... so let me pull my lever again and see why I'm not completing my ground then..

thats weird, a ground wire that carries current.
I guess I'm struggling to understand how creating a "short" causes the relay to click open.... It seems like there should be a 2nd wire that completes the circuit or something...



brant

there *is* a second wire!

it goes from your chassis to the - post on your battery!

here's how the current flows (quick & dirty):

12V from battery + -> relay board -> heater lever -> chassis -> battery -

Andy

think about it this way:

if you had a red 12V wire going from the relay board to the lever and then a brown ground wire going back, where would the ground wire go?

exactly! it's redundant, so why not leave it out and just connect the lever to ground right away ...

remember, the lever does not switch the blower directly, it switches the relay that powers the blower.

all you need to do is to complete the circuit for the switching current ...
Andy

that makes sense...

thanks andy
thanks dave

thanks all...

now who is going to come over and pull the stupid center console for me?

happy turkey day all
brant

I've had trouble with 2 of these levers. Even though it looks like the lever is grounding out the 1 wire, the electrical connection through the lever body to ground isn't robust and may not actually ground the wire when pulled.

Check this:

Test 1) with the lever removed, ground the wire to a good ground and see if the relay kicks in. If relay energizes with the wire grounded but not with the lever, then the ground in your lever is suspect.

Test 2) pull the heater relay and find the connector pin which goes to the lever. From this pin, measure resistance to ground to test the lever. When the lever is fully pulled, your volt-ohm meter should read about zero ohms. If it reads a high resistance, then the lever is not making a good ground.

Spoke

thanks spoke!

I'm suspecting the quality of the ground also.
last saturday I removed the console and lever... and all

per your test #1, yes.. when I had it all disassembled and touched the single wire to chassis, the relay clicked and fan started running.

so I cleaned the chassis a bit where the lever bolts down and then cleaned the connection for the single wire onto the lever. Everything was working.

I reassembled everything (put the console and carpet back) and 4 hours later drove the car to find it NOT working any longer.

I'm going to test the switch further and maybe add an auxillary ground wire as well.

For one of my levers, the ground through the lever body was so flaky that I ended up strapping a very fine piece of brass wire between the contact and ground.

Most likely the problem isn't the ground to the lever body, its the lever contact to its body that is not making a good connection.

Maybe take the lever apart and clean each component and re-install.

Spoke

Exactly. the contact is not making contact. the electrical part to that point is working which is a good thing.

A simple tweak of the contact and lever is all you need.