96 Celica GT Service Reminder Indicators Not Working

[tffav]

I have a 1996 Celica GT and I am having problems with the service reminder indicators within the instrument cluster panel. I recently had the car inspected in Pennsylvania and I was told that some of the service indicators were not working so they failed the cars inspection. Some of these indicators should illuminate when the ignition key is turned to the ACC or ON position(s). Currently, the only indicators that light up when the key is turned to the ACC or ON position are the SRS Airbag Warning light that stays lit for about six seconds, the BRAKE indicator, the low oil pressure warning light and the bing bing bing sound that my seatbelt is not fastened with no indicator light showing up in the instrument cluster. The CHECK ENGINE and the ABS lights do not light up either.

I removed the instrument cluster and found the CHECK ENGINE bulb was blown so I replaced the bulb and reinstalled the instrument cluster. Per the manual, I checked the 7.5 amp fuse labeled 'instrument panel lights' in position #22 per the diagram and found the fuse to be in good working order. I also checked the 10 amp fuse labeled 'gauges and meters' in position #32 per the diagram and found the fuse to be in good working order. No change to the status of the lights as described above. My daughter did assure me that these lights worked at some point over the past year (she was away at college).

Any help would be greatly appreciated.

Thank you!

[alltracman78]

The ECU grounds the MIL to turn it on, so you should have 12v at the MIL wire [W pin] at the ECU. I don't remember which pin it is, you'll have to take a look at the wiring diagrams.

All you need to check it is a test light. Ground the test light clamp on one of the ECU brackets, disconnect the connector from the ECU and touch the point to the W pin on the connector.
It should light up.
If it does your ECU is bad.
If it dosn't you have a broken wire somewhere [or the circuit board for the combination meter is bad].

ABS should be the same thing, I don't remember which pin it is though.

[tffav]

Thanks alltracman78!

I have to admit, I am in uncharted waters here but am more than willing to give it a try. I need to fing the location of the ECU and how to get to it to do the test. Also, I need to find the wiring diagram(s) to tell me the location of the W pin. I have been searching the internet all morning.

FYI, I did have to replace a blown MIL light bulb (is was broken in half when I removed the bulb holder). As a check and before I posted my original thread, I replaced the MIL bulb and then switched it with Trans O/D bulb from just above the MIL bulb. The O/D light has always worked. I reconnected the console and turned the key to the on position. I hit the O/D button on the gear shift and the O/D light lit up. The MIL still did not light up. Maybe usless info here but I just wanted to make sure that it was not a bulb issue.

I hope that the problem is not the ECU. If my research is correct, the ECU is a pretty expensive part to replace (toyodiy.com, computer, engine control, Part #89661 $1,733.00). The circuit board is less expensive by far. The ECU looks like it is located in the center console above the transmission shifter under the radio.(?) I'll look through my Haynes Manual for a wiring diagram.

Finished the rear brakes and struts over the weekend (1st time for everything). Also have to tackle a broken washer fluid hose somewhere in the passenger front wheel well..can't get to it from under the hood.

Thanks again for all of your help.

[alltracman78]

IIRC the ECU is actually under the heater core [you don't have to pull that to get at the ECU].

Pull up the passenger side carpet at the front corner closest to the middle of the car.
You should see 3 connectors and a wiring harness running across the edge of the floorpan.
This is the ECU.

IMO Haynes isn't all that helpful when it comes to wiring diagrams.
You're much better off getting a set of factory repair manuals.

If you do a search for celicatech they have the manuals online that you can look at.
You do have to sign up to get onto the site, but there's a wealth of info on there.