I've been getting horrible gas mileage since I bought the car a few
month ago, averaging 13-15mpg. Car is fully tuned, new ECT, all fluids
changed, etc and nothings changed. My last tank which was virtually all
highway resulted in 16.5 mpg. While cruising on the highway I noticed
my OD switch doesn't work. According to my manual I should get an up
arrow in the dash when its off and nothing when its on which should be
the default setting. Pressing the button on and off nothing happens
either with the arrow or with trans operation. As far as I can tell its
set in the off position meaning its locked in 3 speed operation
although theres no arrow on the dash. I'm not noticing a 4th gear shift
which would partially explain the terrible gas mileage. At least on the
highway. Any suggestions on how to check/repair it? The manual says it
should be getting voltage constantly and the switch cuts off juice
shutting off od. I'm thinking check for power at the switch. Is there a
relay somewhere that may be bad? TIA

Dave
89 740T Wagon