A couple months ago I picked up a '96 GT for a project car. I have it nearly drivable, except the speedometer isn't working. A, what looks to be, new speed sensor came with the car and a second dash came with the car. So far nothing has worked. I had the new speed sensor put in, but no love. The old speed sensor is still showing a resistance with my multimeter, so I am assuming that isn't the problem. I have taken apart the first dash and it was looking fine except for a few burnt out bulbs.
The check engine
light is on, the low oil level light is on, and the air bag warning light is flashing. Hopefully tonight I can get an OBDII reader on the GT, but without the code(s) the speedo problem is looking to be either the wiring harness or the ECU.
Assuming the dash and speedo sensor are good is there anything else to check besides the ECU and wiring harness?
Also, if it is the ECU are there any programmable/more modern ECUs for the fourth gen mustangs?