Hey everyone,

searched the archives - not yet found the issue.

I need to know where to find a schematic for the wire harness at the vacuum lock pump.


Here is the rest of the story - if you are bored...

For starters - the tech help info I found was all slightly different than my model.

I have a 91 300e and the round harness at the vacuum pump has 4 wires - green / blue and two yellow.

I have a 3 second delay keyless unit from JC Whitney that will shut the locks down - and just after they are all down, they pop back up. If I grond the correct terminal my self (instead of the keyless) for a split second longer - they stay down. up function works correctly.

It appears that after the 3 second ground signal from the keyless - the system defaults to "open" status when the ground is removed - maybe a default so if you loose signal to the pump, the locks pop open for safety??

Does anyone know the color coding of my harness from the '91. It appears that I am tapped into the correct wire - as I am getting results - but need to find a way to control the ground (for the down lock function) better.

By the way I checked online and the crutchfield REC-11 unit is also a 3 second delay, so I know I have a long enough pulse.

Also, I do have one slightly slower lock (pass rear) - thought maybe there is a sensor on each lock showing up or down status causing part of the issue.

Thanks in advance,

Don