Hello All,

I'm in bind, the air bag warning light and the fasten seatbelt light are on constantly. The problem is not the sensors, that has already been taken care of. I'm told the problem is that the air bag DERM has failed, GM doesn't sell them any more and the DERM that is in my car is exclusive to the '90 model year. Have any of you run into this before? What do you folks recommend? I live in wonderful State that has very strict inspection rules and the car won't pass an inspection without it. Any assistance given will be very much appreciated!

Keep the rubber side down,

Adam.

 

More times than not the ground needs cleaning. Trying to remember where it is on the 90's. Seatbelt light is very common. I want to say its on the drivers side framerail, Ill have to look it up to be more specific. In fact I think its listed in the "tech tips" section. Big help, huh?

 

What state are you located in? Airbag regulations vary "widely" state to state. In maybe '96 or '97 I saw an owner dispute his rejection for a "deployed airbag" and a State Trooper who policed the Inspection Stations was called and the car taken back to the inspector. The car was "passed" and at the time it had to do with language that an Airbag was a "supplemental device". Belts were operational and that satisfied the requirements at the time! Has it changed? I don't know. I believe the SIR lamp needed to be defeated to comply. If it was lit the bag needed to be there if not lit belts were fine.I sure didn't believe it at the time.
Before ruling out all other components and going for the DERM I'd start with the basic stuff! Confirming grounds, connections(for corosion), the coil(clock spring) etc! First generation systems are tougher to diagnose, there's no plug in the scanner and go to the failed components.
How long have you owned the car? New/used, miles etc. If the airbag was deployed later than '92 the system could likely have been replaced by the later componets. I don't recall if the DERM was one of the required componets or not but the bag and coil were for sure later components.
Have you had any recent work done in the steering column or under the drivers side dash? Have you been into the center part of the dash in the vicinity of the radio, AC controls etc?
BTW ..I have a DERM from a '90. This was purchased as being removed from a running car with "NO DEPLOYMENT"! I trust the fellow I bought it from!

 

I live just South of Portland, ME and the law is if the air bag warning light is illuminated then the car automatically fails the inspection. The inspectors are supposed to check that the lights come on when the car is started, and if they don't then the car fails. Not fun! I bought the car used, about three years ago, its got 115K miles, original Z51 car with a six-speed. The title was clean and I ran it on carfax and it came back clean on that. It's in very good shape, a few things needed to be fixed when I bought it, A/C, radio is on the fritz, typical 100+K mile car. I have done quite a bit of work under the dash actually, had to change out the heater core and had to take almost all of the dash out. It you've got a '90 DERM, I may be interested in buying it if you're willing to part with it!

Thanks,

Adam.

 

I've got a '90 and needed a new derm too. I found one on ebay for $25. The 90 derm was offered in other GM vehicles as well. Search on the internet to see if you can find the correct part number for a 1990 derm, then type that into ebay and you may have some luck.

Also, I had my airbag light on one time and after purchasing a 90 airbag reset tool from MidAmerica, I was able to reset the light. No other problems. Reseting it made my airbag light and fasten seat belts light go off.

 

Mine was the same showed no ground on front l.sensor (code 14). Those things are sometimes hard to re-set and takes a couple of times. Grounding a and k turn to on position, wait till inflat. flashes unground 3 seconds. After 3 seconds ground again for 3 seconds then unground for 10 seconds.
At this point you can ground it again and if code 12 comes up 6 times you ar e successfull. Took me about 3 attempts to get mine to clear which will also turn off saetbelt light.
These instructions are out of my G.Kilibrew code reader, and he states the derm is sometimes hard to re-set.

 

Thank you all very much, your tips have given me a place to start.

 

Hey guys most of the time the frame rail sensor is what goes bad setting off the code and light in the DIC. Before doing any work on this system disconnect your battery! The sensors can be accessed by taking the side gill panels off. They are sitting on the frame rails very close to the firewall. One is under the Battery the other under the heater blower box. They are still available from GM for $60 bucks. To remove them use a 10mm wrench take a dremel tool or grinder and clean the area underneath where the sensor sits also the sensor base itself. I put 2 star washers on the bolts to help make a better ground. Also smear a little dielectric grease on the base of the sensor before reinstalling. If they need to be changed the wires go through the firewall and connect at the base of the footwells under the carpet when you pull it back. There is a specific ohm reading on the plug pins from the sensor. Let me know if ya need em. Mid America makes a neat little tool to clear the code out after the repair for $20 bucks plus it gives you a couple of the pages from the GM service manual with the codes listed and the ohm specs. Let me know if I can be of any more help to you guys I've fixed 8 of these allready for guys in the vette club GOOD LUCK Pipe