Vintage Air Gen IV blower problem

[debarba]

Hi, I have this installed in a '73 Z/28 that, never had A/C. System worked fine when first installed - after restoration work, I've had the following problem. When I turn the key to "On", all blower functions, speeds, etc. work perfectly. When I start the car, the blower is erratic and the blue light along with the backlight flashing on the control panel. Power and grounding have been extensively checked...the 2 white wires are securely on the "-" post of the battery. The HCV relay has a secure ground to the chassis. I've put an oscilloscope on the 12VDC and not a hint of any noise or spikes. I've tried with the alternator disconnected so my 12V is from the battery...no change. The calibration of the blower motors works fine...no surprise since it's done with the engine off. Anyone ever experience something like this before? The other thing strange is when I move the lever to "Cold" the compressor relay clicks so I checked the voltage getting to the compressor and it was about 9.5VDC. Is this an indication of a problem...shouldn't it be a full 12V at that point? Thanks for any help...Bob.

[sheck44]

Hi, I have this installed in a '73 Z/28 that, never had A/C. System worked fine when first installed - after restoration work, I've had the following problem. When I turn the key to "On", all blower functions, speeds, etc. work perfectly. When I start the car, the blower is erratic and the blue light along with the backlight flashing on the control panel. Power and grounding have been extensively checked...the 2 white wires are securely on the "-" post of the battery. The HCV relay has a secure ground to the chassis. I've put an oscilloscope on the 12VDC and not a hint of any noise or spikes. I've tried with the alternator disconnected so my 12V is from the battery...no change. The calibration of the blower motors works fine...no surprise since it's done with the engine off. Anyone ever experience something like this before? The other thing strange is when I move the lever to "Cold" the compressor relay clicks so I checked the voltage getting to the compressor and it was about 9.5VDC. Is this an indication of a problem...shouldn't it be a full 12V at that point? Thanks for any help...Bob.

Hi Bob, sorry I just saw this and I'm not on this site a lot anymore
So, I have to say I have had nothing but problems with the last few systems I have purchased from VA including your issue.
We went over mine a 100X and back and forth with VA and then finally said ... (and VA disagreed) it HAS to be the ECU
Changed the ECU and guess what ... works perfectly !!!

Going to try Restomod on my next project

Cheers
Steve