Georgia Fiero Club Forum

All Things Fiero => Tech Tips, Tech Questions => Topic started by: Donster on January 26, 2012, 11:40:25 am

Title: Stumped again! Heater/AC fan won't run
Post by: Donster on January 26, 2012, 11:40:25 am
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: TopNotch on January 26, 2012, 03:27:43 pm
Check out this thread (http://www.fiero.nl/forum/Forum2/HTML/114136.html) 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.
Title: Re: Stumped again! Heater/AC fan won't run
Post by: TopNotch on January 26, 2012, 03:40:22 pm
While you're fiddling with your fan, check for leaves in the resistor pack. Check out this video:
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on January 28, 2012, 09:38:44 pm
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on January 28, 2012, 09:42:00 pm
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on February 18, 2012, 10:36:11 am
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on March 09, 2012, 07:47:00 am
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Fierofool on March 09, 2012, 08:31:55 am
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. 
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on March 09, 2012, 08:37:33 am
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
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on March 09, 2012, 10:27:26 am
Ditto. It's easier to get to than the starter.

So true ;D

\D
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Fierofool on March 09, 2012, 10:51:21 am
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.
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Donster on March 09, 2012, 10:58:17 am
I'll look into that also. She's got a combination of automatic and standard steering column ;D

\D
Title: Re: Stumped again! Heater/AC fan won't run
Post by: Tha Driver on March 09, 2012, 01:44:14 pm
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.  ;D  I think it's easily adjusted at the shifter just haven't gotten around to it.
~ Paul
aka "Tha Driver"

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