The rear window defogger relay on our 1986 911 Targa doesnot activate the upper and lower defogger elements with 12 VDC.

There is only a very small voltage (.27 VDC), (circuit leakage?),on the Red/Blk wire from relay contact 87a to the upper and lower parallel elements when the defogger button is engaged on the console.

Should the time delay? Time constant circuit? at some point, engage relay #2 and apply voltage (12 VDC?) onto the upper and lower elements?

How does the upper and lower element sequencing occurs, and how much voltage should be at the input of the upper and lower elements?

The voltage on the Red/White wire from relay contact 87 to the
center element indicates 12 VDC as the relay #1 coil is not wired through the solid state timing/time delay circuit.

Notes:

1. The defogger relay p/n 911-615-115-00 is new.

2. Continuity checks indicate that the elements are intact.

3. All other voltages/grounds are as required.

Try this link to the Pelican BBS. Sign up for the BBS and post your question, or search. Pelican also has some excellent wiring diagrams on-line.

http://forums.pelicanparts.com/forumdisplay.php?f=8

Good luck