Rosadoc-Z

Hey guys, I need help in figuring out why my fasten seat belt, parking brake, and SES light dont come on when i turn the ignition. I have never seen these lights turn on since buying the car a few weeks back. I've checked the fuses under the dash but i'm thinking some of you guys would know what could cause this? Oh by the way, the warning chime/buzzer stays on for a really long time when starting the car.

fisherbody86

First, check to see if they even work. Pull the parking brake and see if the light comes on. And to check if the SES light works, unplug the mass air and start the car. If they still don't light up, chances are someone pulled the bulbs or something. If they do work, well, then you have some diagnosing to do.

Rosadoc-Z

I've already tried all that. What I havent done is check if there are even bulbs there, maybe someone did pull them. But if they are there, is there anything else that could cause this?

fisherbody86

I don't know if the bulb check is powered by the ECM or if there is a seperate circut coming from the ignition switch. If we could find a firing diagram and take a look at it, I'm sure we could diagnose the problem without even busting out a test light. It is very suspicious that all three of these lights don't work at the same time. I'm sure it will be easy to spot with a wiring diagram.
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I'm going to look for a diagram right now.

Rosadoc-Z

Well in case anyone was wondering if it is ECM related, I tried swapping with another ECM i had and that didnt fix the issue either. If anyone has a diagram for an '87 350 please let me know.

fisherbody86

I found a diagram at work, but I forgot to print it out and bring it home. The warning indicators in question here are all powered by the gauges fuse, then power travels up to the dash to the bulbs themselves, then to the parking brake switch, seat belt switch, etc, which grounds the circut. The SES light runs into the ECM where it controls the ground for that light bulb.

So break out a test light and test for power at the "GAUGES" fuse. I know you said you checked the fuses visually, but test to see if there is power coming into and going out of the fuse. If so, then there is a broken wire between the fuse box and the connector behind the I/P. IF not, just temporarily put power to it using a jumper wire from another fuse to see if the lights come on. If that fixes it, then you have a broken wire going into the fuse box from the battery.

If you already swapped ECM's with a known good part and the SES light still didn't light up in the bulb check, then we can rule out a bad ECM or any other wiring between the I/P and the park brake switch or seat belt switch because the chances of there being a seperate problem in all three of those circuts at the same time is slim to none.

I will print out the diagram and scan and post it tomorrow. Hope this helps.

Rosadoc-Z

Thanks for the help. I pulled out the instrument panel this morning and all the bulbs seem to be fine. I'm gonna go ahead and change them anyway and see what happens. I did notice that the copper lining that is meshed in that plastic covering connecting all the bulbs in the I/P (sorry dont know what its called) has a few very small holes throughout it. Not sure if that would cause the problem. But one other thing i forgot to mention was that the right turn signal light also didnt work. the turn signal switch and light on the outside of the car work fine, just the bulb that doesnt flash.

Well like i said, i'm gonna replace all those bulbs right now and go out and get a test light for the fuse. I'll update as soon as something happens

Rosadoc-Z

after taking out the I/P, all bulbs seemed to be good but i went ahead and cleaned the connections and added a little electric grease and replaced the bulbs. Now, I got the SES light working, the turn signal light is working, and the fasten seat belt light comes on every once in a while. The parking brake light has yet to work. So i'm assuming all it needed was a little cleaning the copper surrounding the parking brake light seemed pretty coroded. and after trying to clean it, it still didnt work.

Vader

Disconnect the connector from the brake pressure differential switch and ground it. With the ignition turned on, the BRAKE light should operate.

neilcase

I realize this is a really old thread but since I landed on it I figure others will too and I'll throw in my two pennies. I have 3 Third Gens in various states and recently I decided to get ALL the dash lights working. Took me an entire day. Here's what I discovered. FIRST: Per the manual there are 2 different bulbs to use. One is a 2.7 watt with a common nomenclature of 161 and the other is a bit brighter at 3.3 watts called a 194. You can get these at most auto parts stores.

I took EVERY single bulb out of 3 sets of dash carriers and bench tested them and finally got to a point where I knew I had 54 working bulbs (there are 18 bulbs in each of mine, yours might vary). I started re-installing the carriers and found that some of them STILL did not work. What I never suspected was that the little plastic individual carriers ( I don't what the correct name for them) that each bulb plugs into and then screws into the large carrier is capable of failure too! I had about 10 of these gone bad. So after ensuring that all the bulbs and all the individual plug in carriers did in fact work, now I have 3 complete and working sets.

Moral of the story. Make sure you use the correct bulb and in addition to checking the bulb, check the plug in carrier too! They do go bad.