I'm troubleshooting the drivers side window and am completely baffled.  When I pulled the window motor, it was easy to see the problem.  The spring snapped and burned up the motor.  I ordered a new motor and spring.  Using a voltmeter I have 12 volts at the blue and brown wire in the door when using switch in console.  When I hook up the motor, I can get the up side to work but not the downside.  I'm lost because they both work when testing with the voltmeter.  In the corvette shop manual it recommends replacing switch when only one side works but that doesn't make sense to me if they both work when tested.  What am I missing?  It's a 1979 coupe.

|UPDATED|8/1/2018 1:50:57 PM (AZT)|/UPDATED|

Welcome to the forum. Can you back probe the connector after it's connected to the motor? If you still have 12 volts there but the motor still doesnt work then I would suspect the connector first or the motor second. To check the motor, you can connect it to your battery or other 12 volt source directly to see if it runs in both directions.

|UPDATED|8/1/2018 2:43:13 PM (AZT)|/UPDATED|

Thanks for the info.  That is exactly what I did and found that the switch wasn't working correctly.  I've ordered a new one and am certain that will fix the problem.  Not a fun job installing a power window motor on a 79.  Now I'm on to the power locks.

You're telling me. I put factory air and power windows on mine about a year after I bought it new. Not a lot of fun, especially the windows.

The thing you have to remember is your meter has a really high impedance. which means it puts almost no load on the circuit. At 9 VDC and no load it will show 0 or very low ohms which could mean a good switch, but if the contacts are burned , when you put 10 or 12 amps across the contacts of the switch no current will flow and the motor will not work.

One thing my mechanic told me about C2/C3 windows being 'slow', before and after motor replacements, is dealing with entire window assembly even though you are only focused on 1 issue. It will pay off. Here's why! Last century, when the C2 and C3 were built, the factory loved using gobs of the white lithium lubricant, on EVERYTHING mechanical. While it did provide great lubrication for it's day, over time it became a magnet for everything dirty. That alone over the decades would gum up any and all systems.




|UPDATED|8/7/2018 6:05:37 AM (AZT)|/UPDATED|

Years ago I had the same problem and found the switch was not working.I bought a new switch and proceeded to replace switch.When I got to the switch and took it out of the console.I found a sticker from an apple I had eaten and the sticker somehow got between switch and electrical plug..Switch I took out and replaced is still with me and in working order????? Good Luck...