: AAARRRGHHH...Where's the #$@#) switch?!?!

07-08-04, 06:03 PM
I'm getting IO27 and PO91 codes on my 95 SLS which points to a TR / PRND321 switch failure but I can't locate it to check it out or replace. The car runs pretty good but the SES light comes on after driving about 2mins.

I understand the basic operation of the TR switch, but is there another sensor tied into the switch?


07-08-04, 06:14 PM
Open the hood and look on top of the trans. You will see where the shifter cable connects to the shift arm on the trans, the box with the connector connected to it is the one you are looking for.

07-09-04, 06:03 AM
Found it! Thanks dude. I reckon I should have been wearing my glasses when I was looking for it before. Does any one know if the switch is repairable or adjustable? Once I saw the size of the switch I figured it's going to be a dealer item and it looks like it's going to be EXPENSIVE! My fiance is in college so I'm working on a very very tight budget....


07-15-04, 06:07 AM
I've done a search on all the forums concerning this switch and really can't come up with anything. Is this something that is uncommon to fail? It looks like there are 3 screws on the cover which leads me to believe that the switch is actually servicable (adjustable). I don't have the $80 to replace it at this time and really would like to get the SES light to stay off for more than 5min. Any info would really be helpful


07-15-04, 10:46 AM
The switch is adjustable. However the manual talks about an "alignment tool". It also makes mention of "If the pin is sheared, check for a cracked carrier". Having never messed with this switch on the 4T80E I can't help much more than that. I did adjust one on a 4T60E once and it was much simpler. Just insert a pin (drill bit) in a hole and adjust). Maybe a trans shop will adjust it for a couple of bucks. Couldn't take more than 5 min.