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Old 08-21-2013, 11:45 PM   #1
CorvAdel
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Default DERM query..

I don't have a 1991 FSM.
If sir/air bag deploys is it necessary to replace the DERM?
Are there any other procedures needed to bring vehicle back to safe, driveable condition with respect to this system apart from replacing air bag in the steer wheel?
Thx
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Old 08-22-2013, 11:35 AM   #2
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From my 91 FSM:
Click the image to open in full size.
Click the image to open in full size.
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Old 08-22-2013, 11:38 AM   #3
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Shoot me a PM if you need info on anything else. Not an expert by any means but I can copy pages of the FSM for you if any more are needed.
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Old 08-22-2013, 06:10 PM   #4
xflagz51
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If I'm not mistaken both the DERM and sensors are not longer available from GM, but you may be able to get them from salvage yards if you need them. I tried to find a sensor last fall I think, no dice. It's going to be interesting to see how these cars are treated by the States when these parts no longer available and the cars can't pass inspection without them.
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Old 08-22-2013, 08:48 PM   #5
CorvAdel
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Thx to both replies, esp Ron.
I now just have to identify all of those parts and locate them! Does the FSM show their locations?
Thx. I appreciate the assistance.
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Old 08-23-2013, 12:12 AM   #6
WVZR-1
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Quote:
Originally Posted by CorvAdel View Post
Thx to both replies, esp Ron.
I now just have to identify all of those parts and locate them! Does the FSM show their locations?
Thx. I appreciate the assistance.
Generally speaking if there's a deployment the wire on the coil/clock-spring will burn, you can check the coil for continuity and for a '91 I believe if the coil is fine and you've got an air-bag you can scan the DERM for errors. You would only need to replace the appropriate sensors to clear the codes. The FSM displays all. The DERM is the most difficult to locate and remove from the car. Do you have an air-bag yet? I believe I have the air-bag, and a coil for a '91. I don't have the arming sensors or a DERM.

The terminology and the "required statements" in the FSM are a CYA statement I believe.

Last edited by WVZR-1; 08-23-2013 at 12:23 AM.
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Old 08-23-2013, 12:17 AM   #7
WVZR-1
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Quote:
Originally Posted by xflagz51 View Post
If I'm not mistaken both the DERM and sensors are not longer available from GM, but you may be able to get them from salvage yards if you need them. I tried to find a sensor last fall I think, no dice. It's going to be interesting to see how these cars are treated by the States when these parts no longer available and the cars can't pass inspection without them.
The safety inspection requirement in some states don't require an SIR system to be operational. I've seen a current then '98 model GM vehicle with both bags deployed rejected at a Virginia inspection station only to be over ruled by a State Trooper on visual inspection of the vehicle. At that time the SIR wasn't a requirement. There were many conversations about that one.

Rental fleets were delivered with a "side curtain delete" option and that created quite a commotion when the rental fleets put these cars on their "for sale" lots or they were sold at auction without disclosure. I believe there was a "disclosure" mandate in some states but not all. It's not done that way now.

Last edited by WVZR-1; 08-23-2013 at 12:31 AM.
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Old 08-23-2013, 04:17 PM   #8
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I scanned the pages for you. PM me with your e-mail address and I will send them to you. I also scanned the table of contents for the SIR Diagnostic section. If you want to see the 70 pages that it contains then let me know as I will have to take that heavy-azzed book to the copy center and then charge you for the copy and mailing costs.
It is just too much for my little desk top unit to deal with.
I'm retired now so don't mind spending the time to help a brother out though. Don't be afraid to ask as others here have done even more for me in the past.
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Old 08-25-2013, 10:22 PM   #9
CorvAdel
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Thanks to Ron for the scans.
I still am not sure that the DERM needs replaced. It appears that only the sensors need replaced after a deployment.
I need to know for sure as parts for these cars are not easily found in So Australia.
Maybe I will replace the sensors with the air bag and see which error codes come up.
Thx to all who have taken an interest.
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Old 08-25-2013, 10:55 PM   #10
WVZR-1
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Quote:
Originally Posted by CorvAdel View Post
Thanks to Ron for the scans.
I still am not sure that the DERM needs replaced. It appears that only the sensors need replaced after a deployment.
I need to know for sure as parts for these cars are not easily found in So Australia.
Maybe I will replace the sensors with the air bag and see which error codes come up.
Thx to all who have taken an interest.
Does the SIR system need to be "functional" and free of errors there? Some have always thought myself included that the early SIR systems were quite dangerous because of the "power" of the system. There's never been a study that I'm aware of that says that they're less or maybe more dangerous with "age"! If you've a requirement for just a "lights out" at key-on and are concerned with the early system possible dangers the system can generally be easily bypassed to put the lights out with a 2 Ohm resistor at the air-bag connector.

SIR and seat-belt warning should respond normally to the key-on requests.

Last edited by WVZR-1; 08-25-2013 at 10:57 PM.
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Old 08-26-2013, 12:49 AM   #11
gerardvg
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Quote:
Originally Posted by CorvAdel View Post
Thanks to Ron for the scans.
I still am not sure that the DERM needs replaced. It appears that only the sensors need replaced after a deployment.
I need to know for sure as parts for these cars are not easily found in So Australia.
Maybe I will replace the sensors with the air bag and see which error codes come up.
Thx to all who have taken an interest.
PM sent in regards to Corvette parts recycler in Victoria Australia.
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Old 08-26-2013, 12:49 AM
 
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