There are two screw terminals on the power module under the helm labeled power wedge (black) with a black wire, and power wedge (white) with a white wire (see previous photo).  You can switch those wires to make the power wedge move opposite of the way you are controlling it with the MUX.  Using a voltmeter to test the voltage and ground on those terminals when running the wedge up or down can also help determine what the problem may be. 

Please don't overlook the other suggestions.  The most common issues I've seen after actuator replacement is loose electrical connections, the wedge wing binding, or the power wedge adjustment bracket not being properly adjusted for the actuators. 

... and that means that if it is really a straight pipe thread, it should be 1.5" pipe.  That would also make it actually 11.5 TPI.  Hard to measure the cap with the huge flange and all.

Edit:  I just compared it to a pipe thread, and it looks like 11 TPI rather than the 11.5 that pipe thread is supposed to be.  Total diameter is 3.5" and it is 1" thick, by the way.

19 hours ago, Slickuke13 said:

Hi, somehow I lost the gas cap for my 1999 Malibu Sportster. I know the topic was covered years ago but does anyone have a suggestion for a replacement. Or at least what I can do temporarily.TIA

 

 

If it looks like this, the thread seems to be 1.85" x 11 TPI.

For 2018 21VLX the PN is 5411052.1.   
Just picked up my replacement from Tommy’s. 

Csleaver, thank you so much for the in depth reply. 

Batteries are new and all connections are tight. 

I just checked and Auto Wedge was on. I wonder if the shop even noticed this when they tested the wedge? They just told me the actuators we installed with the wedge in the down position and they could not get it to raise using the MUX switches. 

I am not beginning to wonder if I should put it in the water and run the wedge down and then try calibrating. My only concern is if the wedge will not raise back up. How do you swap the power connections to "fool" the wedge? I may have to do this if it will not calibrate and raise.