I was trying to read codes That are stored, if any. And when I jump the ALDL the shift light comes on and no check engine light. What can cause this? I have an 86gt 4spd.

Without jumping ALDL connections and Key On - is Check Engine Light ON?
(asking to make sure CEL bulb is not burned out)

Do you jump ALDL connections, THEN turn Key to ON position?
//www.fiero.nl/cgi-bin/main.cgi?ECMCodes

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Check engine light does not come on when the key is on. How would a bad bulb make the shift light come on?

quote Originally posted by M.aaron80: Check engine light does not come on when the key is on. How would a bad bulb make the shift light come on?

It may not be a bad bulb....it may be a bad ECM. Replace the bulb to find out.

[This message has been edited by Gall757 (edited 05-22-2020).]

quote Originally posted by M.aaron80: Check engine light does not come on when the key is on.

That makes reading codes a whole lot more difficult. You need that light to be working. As mentioned, check to see if the bulb has burned out.

Are you absolutely sure you're using the correct terminals, as sometimes the ALDL connector is mounted upside down?

quote Originally posted by M.aaron80: Check engine light does not come on when the key is on.

So.... did you fix this and get the ALDL Codes?

No, I can’t find the problem

The problem is my bulb!

quote Originally posted by M.aaron80: The problem is my bulb!

So with the new bulb are you getting any codes? I was thinking perhaps the CEL was burned out because it was ON all the time ...