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View Full Version : '90 MY "shift light" ?


WVZR-1
05-07-2014, 03:26 PM
From a conversation over in the CF for an L98 BUT after checking the FSM for the LT5 the instrument cluster mentions an "upshift light/tell tale" (NOT RELATED TO 1 - 4). The 90 FSM it's in 8A-22-A and you'll see both shift and the 1 - 4. I've never seen it on mine but my spare cluster has a bulb socket in the correct position. I didn't remove the backing plate to check and likely won't to see if there's a bulb. The bulb placement is on 8C-33 #12.

Was it maybe never implemented and just an engineering thought? Anyone seen it actually work? I don't recall it ever being discussed. In the L98 schematic there even seems to be a provision for an "overdrive" lamp.

I don't see it in the '91 FSM in a similar location but I didn't look very hard. The cluster illumination on 8C-42 still has reference to it though.

Kevin
05-07-2014, 03:50 PM
the upshift light is in the dash cluster near the top left if I remember correctly. I have have marc redo my chip to get it put back in. last time i saw it was in 06 I THINK 90 is the only year to have it

8cam
05-07-2014, 04:09 PM
GM's updated calibration for the '90 actually disabled the shift light, so it might have been there from the factory but was removed with a service update. Marc has the details on his site.

http://www.zr1specialist.com/HAT%20Web/products/Calibration%20AYBKG.htm

WVZR-1
05-07-2014, 06:26 PM
Can't imagine my not knowing/remembering that but sh!t happens I guess. I thought I had notes for all of the early revisions to the PROM. Guess I'll not be concerned.

gbrtng
05-07-2014, 07:39 PM
I see that indication on my 91 when I stay in a lower gear for an extended time - example = driving in 5th for several minutes at (say) 60 MPH. There is also a 1 to 4 indication ...

WVZR-1
05-07-2014, 07:45 PM
I see that indication on my 91 when I stay in a lower gear for an extended time - example = driving in 5th for several minutes at (say) 60 MPH. There is also a 1 to 4 indication ...

I didn't find it in the FSM in a similar location as the '90MY information. Have you seen it in the wiring for the ECM for your '91? Is it mentioned in your owners manual? The upshift isn't related to the 1-4