Mity2

as title says..
My 95 have no heat at all. I bought it like this(My mechanic feels if I put aide about $1K, I should be able to cover most sea outing with my family),
I also looked at right night shiftle there is no coolant leakage, and both in/out cooling line was hot, I figured its either blender motor itself(linkage?), or the box that all the vacuum line line from A/C/Heat control module, blocken plastic arm, whatever.

Anway, I want to see if anything happening to this control unit. but I don't know where it is

pcolt94

There is no linkage for the blend door, it's a direct shaft connection.

Pull the blower control module out of the top of the evaporator box and look at the blend door. Set the fan to lowest setting and run the temperature control to 60, then 90 and see if the door changes position. Depending on results, go from there.

Mity2

Mity2

Ok so I open the evap, and did the what was suggested above.
Door wouldn't open on its own. So I used long screwdriver and forced the door open, and heat started to work like nothing happened.
So at least my heater core is getting heat/no clogs. That's plus.
With heat back on, everything else worked - The LCD turns on with correct read out. operating mode selector works between high level, bi level, and low level. Defroster blows from correct vent
And self check revealed no code.

So what does this mean? Do I need to go get new diverter actuater(electric motor? vacuum driven actuater?) or do I order repair parts kit from Batee.com, and have at it(Im(was) MECP certified tech, so perfectly comfortable doing my own repair using their kit(http://batee.com/corvette/dcrg/services/9096_c68_rebuild.html) ?

belairbrian

You need to drop the hush panel and check the blend door motor. Your 95 has the motor mounted on the bottom of the duct assy.

When GM moved it to the bottom, in 94 IIRC, they made it much easier to service. But they also put it where any leaking from the heater core, or condensation if the condensation drain clogs, can get in it and ruin it.

Mity2

PatternDayTrader

Not by forcing it with a screw driver …

pcolt94

Do all the buttons on the controller head work?
Does the controller display ever go blank or show dashes?
Does the temperature control on the head go from 60 to 90 correctly?

If there are no discrepancies with the above questions, then the basis of the control head and programmer seem to be OK. So I would then think the motor might be the cause of the problem.

I have been bee repairing the programmers for a long time without the kits (never knew they existed) and if all above is OK, doesn't sound like a kit will help at least at first indication.

If you moved the door with a screwdriver, I don’t know what if any damage was done. The motor output shaft cannot be turned due to the gearing of the motor assemble. The connection to the blend door is a shaft one side flat, goes on only one way. If you forced it and broke the plastic shaft of the blend door, you have big time trouble. If you're lucky and it slid around, it would be surprising nothing broke. Could have broke the gears in the motor assembly, that would be better then breaking the blend door shaft.

Mity2

red is me

belairbrian

Here is a good thread with pics.
95 Corvette Blend Motor Replacement

Seems like there is a lot of confusion on pushing the blend door.
Prior to 90 the door was run by an actuator and a link. The link could become disconnected. So for those cars, a GENTLE push to see if the link is off should be OK.
In 90 (think new dash) the Blend motor became a direct drive and mounted on the top of the duct work.
In 94 the actuator was moved to the bottom of the duct assy.
Since 90-96 have a direct drive pushing the blend door is at best risky. Break the end off the door and you are essentially going to be doing a heater core change to get to it.

On 94-96 dropping the panels and removing the motor is relatively easy. The motor will still run hanging loose and connected to the wiring harness. You can watch the motor turn and see what is going on. Also you can move the door by hand with the motor off to check for binds.

Never rule out that a critter built a nest in there.

Mity2

pcolt94

This was water intrusion in my motor. Don’t mess with the gears for they are calibrated with the potentiometer and if you lose the calibration by one tooth you will not get it back right again. It takes a FSM and a good electrical background to get it back working specs.


OK so you want to test it. Pins 5 and 6 are the motor driven by 12 volts and polarity reverses for direction. The motor should measure about 75 or 80 ohms. If that looks good you can apply voltage to the motor and if it moves careful in going past the mechanical limits. A low current power supply works good for this.

The potentiometer pins 8,9,10 can be measured with a ohm meter. It's a 9.5K pot and I can't tell you what it might read as I don’t know what position it stopped at. DON'T put voltage to it.

Mity2

Thanks for the through reply. I’ll check the motor tomorrow.

But it I also got one more question.
so based on what your saying, I should see a voltage(12v) between pin 5 and 6 from programmer side regardless of motor working or not, correct?
while I only had test right today, I saw no voltage coming from programmer side.
or do I need something other then test light to check and see if voltage are being supplied to the motor?

pcolt94

With the motor disconnected and no feedback voltage to the programmer, there is no telling what the microprocessors will do. Basically all bets are off for any voltage readings with the motor out of the circuit. Troubleshooting has to be done with all connected and back probing the connectors to really see what is going on.

Your troubleshooting electronics not fixing a tail light on a 1960s car. Get rid of that test light and get a meter (DVM).