Stumped again! Heater/AC fan won't run

[Donster]

I've put 12V directly to the fan, it runs
Checked the relay, it runs
Checked the fuses, all good
Replaced the switch with a known good one.
 
Switch wil not turn on the fan in any position
 
I know that in the "High" position, the switch circumvents the resistor, so I know it can't be the resistor
 
Anybody have any other ideas?
 
\D

[TopNotch]

Check out this thread on Pennock's. As you can see in the diagram in the thread, the voltage takes a different path at full on, compared to slower speeds. So your problem has to be something common to all speeds. Check the ground wire on the fan motor.

[TopNotch]

While you're fiddling with your fan, check for leaves in the resistor pack. Check out this video:

[Donster]

Roger is the man!
After hours of troubleshooting, he discovered that the brown wire from the switch was somehow not reaching the relay.
After disconnecting the C300 connector, he noticed that the one pin/terminal inside the C300 block didn't even have the wire in it!
I inspected a second harness I had and saw that the same location on this harness didn't even have a pin/terminal, so we figured there must be a difference in harnesses.
Swapped the harnesses and BANG! All working again.
 
I'm assuming that the harness in Anne's 85 was actually from an 84.
I'll pull out Shanine's and look at it to compare tomorrow.
 
Thanks again Roger!
 
\D

[Donster]

While you're fiddling with your fan, check for leaves in the resistor pack. Check out this video:

Thanks Pat.
While I was at it, I used the Shop-Vac and cleaned Anne and mine thoroughly. Had just done Shanine's a while back, after Kevin discovered 78 pounds of dirt in her ducts, which were blocking the actuator motors from running and burning out the HVAC units!

\D

[Donster]

Just wanted to post that I have verified it:
 
The front harnesses (AC fan/wiper motor) for 1984s equiped with AC, differ from newer model harnesses. The newer ones have 2 more wires going to the C300 block at different locations. The wiring for wiper motors with or without delayed wipe also differ between the 84 and newer ones.
 
The other harness (headlights/coolant fan) also differs if the 84 had AC, as it has the two-speed fan relay.
 
They ARE NOT a direct swap
 
\D

[Donster]

OK, got a Rodney Dickman low temp fan switch and all is good regarding the fan, but ............
 
Shanine's 84 just would not be Shanine's 84, if something else would not go wrong again!
Every now and then, when she wants to start the car, the starter won't do anything. No noise, no clicking, nothing. All lights and everything work, just not the starter.
She waits a few minutes, and then the car cranks.
Where do I start looking???
Starter going bad?
 
Advice anyone?
 
\D

[Fierofool]

Two things come to mind.  I've found that today's new batteries usually don't have enough threads in the side terminal for the standard cable bolt to pull a good contact.  I've replaced all mine with long posts designed for hooking multiple batteries in parallel or series.  With the standard posts, low power items will work, but high power items don't.

The other thing is it may be that the ignition switch may be dirty or going bad.  Not the lock tumbler itself, but it's contacts that it operates. 

[Donster]

The ignition switch is a great idea, as I just replaced her steering column, and it might have a bad/dirty ignition switch in it.
Thnx

\D

[Donster]

Ditto. It's easier to get to than the starter.

So true

\D

[Fierofool]

I just remembered that Shanine's car is an automatic.  I don't know how the neutral safety system is set up on the automatic, but is there anything on the column that senses Neutral or Park?  It may be that it's just a little out of adjustment.

[Donster]

I'll look into that also. She's got a combination of automatic and standard steering column

\D

[Tha Driver]

On my Indy I sometimes have to pull back the shifter (but still in park) to get the neutral safety switch to work.  I get in, turn the key, & nothing. I think "what the..." then I remember to jiggle the shifter.    I think it's easily adjusted at the shifter just haven't gotten around to it.
~ Paul
aka "Tha Driver"

Custom Fiberglass Parts