need help with ac problem ..
"oldpro" is maybe a newer userid that you've created - I've seen a couple posts that seem to indicate you've used many maybe for a few years.
Last edited by WVZR-1; Jul 3, 2015 at 10:33 AM.
The Best of Corvette for Corvette Enthusiasts
"oldpro" is maybe a newer userid that you've created - I've seen a couple posts that seem to indicate you've used many maybe for a few years.
A '90 is also a potential C60 (manual) or C68 (automatic) AC option and the diagnostics are all different. The fuse that you mentioned finding hints it's a C68 system but ............
Last edited by WVZR-1; Jul 3, 2015 at 11:40 AM.
A '90 is also a potential C60 (manual) or C68 (automatic) AC option and the diagnostics are all different. The fuse that you mentioned finding hints it's a C68 system but ............
You need a test light or volt meter.
On top of the evaporator housing are two electrical plugs.
One plug has a Red wire. That's 12 volts to power the blower control module and hot all the time.
2nd plug has three wires.
Dark Green/Yellow varying voltage depending on the fan speed setting.
a 1 in the LCD would be slow speed.
a 10 would be high fan speed. This is the control voltage sent to the Blower Control module from the HVAC Programmer.
Purple wire is the voltage to power the Blower Motor and comes from the Blower control module.
Black wire is Ground.
Unplug the two pin connector at the Blower Motor.
Connect red meter test probe to the Purple wire.
Connect the black meter test probe to the Black wire.
Turn ignition On.
Press the Auto button. 2nd button to the right on the bottom row of buttons. Auto LED below the button should light.
Press the Fan arrow up button until you see 10 displayed in the LCD.
You should measure at least 12 volts on the meter.
If you do and the blower motor fan isn't running the fan motor is bad.
If you read zero volts.
Turn ignition Off. (RECONNECT THE BLOWER MOTOR PLUG).
Remove both electrical plugs on top of the evaporator housing.
Place your Black probe on the four pin connector Black wire. (Ground)
Place your Red probe on the Red wire.
Should measure 12 volts.
If zero volts the Fusible link is blown. Its located under the battery
bolted to the battery jumper block.
If you measure 12 volts
Turn the ignition On.
Press the Auto button if it isn't lit.
Press the fan arrow button until you see 10 in the LCD.
Move your red probe to the Dark Green/Yellow wire.
you should measure around 7 volts DC.
If no voltage could be the AC programmer is bad or the Dark Green/Yellow wire is bad.
If you do measure 7 volts and the blower fan is not running the Blower Control Module is bad. The Blower Motor Control module is located inside the evaporator housing. Remove three or four small bolts and it will lift out of the evaporator housing. DO NOT REMOVE THE TWO SMALLER BOLTS OR THE Blower Motor control module will fall into the housing.


Last edited by Hooked on Vettes; Jul 3, 2015 at 04:07 PM.
















