Hello all - I have a 90 740 turbo wagon, SRS light has been on for years, I've moved to Vermont and can't pass inspection with it. I tried the procedure for reading and clearing the fault codes as described in the FAQ, but I get no reaction from the SRS light at all, no flashes after I break the connection after 2 seconds as described in the FAQ. I have replaced the crash sensor and power supply (from a boneyard) and checked all connectors. I believe the electronics are "alive" as I get a reading of about 4.75 volts from the lead from the fusebox (again as described in the FAQ) for about 12 seconds after turning the key to the warning lights on position. It then drops to about 1.5 volts. This is the same behavior I got from the original crash sensor and power supply. Any ideas?
Thanks very much!
Stu

Especially in damp climes, but even in dry ones, the vast majority of problems I've had with SRS faults turn out to be related to dirty plugs and connections. I'm not sure where the lines run on the 700. On the 2 series, the harness runs from the ECU under the driver's seat up the left side of the center dash console where you'll find the yellow plug that is the usual cause. I've also fund dirty plugs at the airbag itself to be the problem. High resistance, no doubt. Sometimes I've been able to clear the fault after simply by unplugging the one next to my knee and plugging it back in, then running the clear code routine. Or, you may have a bad SRS ECU.

"...unplugging the one next to my knee and plugging it back in..."

I've only fixed one ever and this is exactly how I did it. And the connectors and their gold pins looked clean to me.
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Art Benstein near Baltimore

My wife really likes to make pottery, but to me it's just kiln time.

yes, I did look at those connector pins, they did look clean - but I didn't clean them, so maybe that's the issue. I'll give it a go....
Thanks!

Well, if you pulled the connector apart to look at them, you did just as much as I did. I did not expect to "fix" it doing that, but I'm well familiar with the invisible stuff that keeps electrons from flowing now and then in the old cars.

I too would be surprised if, during your emissions or safety inspection, the SRS lamp is part of the check list. It was new in '90 on the 240's I'm familiar with. But, on the other hand, our emission testing cannot proceed if there are any red warning lamps lighted with the motor running; the only one they seem to care about during lamp test is the CEL -- to make sure that one wasn't unscrewed.
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Art Benstein near Baltimore

If life gives you llamas, make llamanade.

"the only one they seem to care about during lamp test is the CEL -- to make sure that one wasn't unscrewed."

Yes, I believe that is all that Mass. is concerned with too. As long as the CEL light works and doesn't light up during the actual test is all the inspection stations here care about. And that is only on cars < 15 years old. Not having a working SRS light was never an issue for me. Maybe it would have been different if it was a 2 year old car?? ...:)

Well, I'll give it a try... I guess that means pulling the instrument cluster to get at the light... I did try cleaning the contacts to no avail.
Thanks!
Stu

Stu,

Think it took me less than hour to remove the bulb in the 240. I also needed to jumper the temperature compensation board at the same time so I killed 2 birds with one stone!

The 740 instrument panel removal might be more difficult than 240. I don't know. Do you have a book or access to instructions? U-tube could also be an option. I suggest disconnecting the battery and the driver airbag sensor yellow connector (under the carpeting near console) at least 1/2 hour before doing the job. May be overkill, but it is certainly better to be safe than sorry!!

Good luck!
Jim

Thanks Jim - I have pulled the instrument panel long ago, as I recall it wasnt too bad... yes I agree about disconnecting the battery well ahead of time! Will post my results down the line when I get it "working" Thanks for all your help! I do have a haynes manual, its been mostly helpful over the last 15 years... but the internet is even better!
Cheers
Stu

Yes - the instrument cluster came out easily, just to screws hold it in. Lotsa connectors to unplug, and the vac line to the turbo gauge. Unplugged the SRS light, took it to an inspector recommended by a friend, and voila! I am legal. Thanks for all the suggestions!

"Unplugged the SRS light, took it to an inspector recommended by a friend, and voila! I am legal."

You're lucky the inspector wasn't trying really hard to fail you. You know that all the lights need to come on when the ignition is turned on to show that they're functioning and the bulbs work. A more sophisticated hack would have been to hook up the SRS light in parallel with one of the other lights.
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1992 745, >500k km (now gone, but not forgotten)

so sages- problem solved but what was the cause and remediation for this problem. were the contacts in the light or bulb stinko ? thanks tons oldduke

Excellent!

Jim

Excellent!

Jim

have to be careful on this one vermont. shyster dealers would likely clip you only $600 to shut off that light. huge variation among the states on auto inspection. fla has none except in a few of its smogged out cities. nj has the worst - much nitpicking and keaster pains over smog failures. they expect you to pay up to $500 for repair to smog devices if you fail emissions. many home runs are hit at inspection stations there. regards oldduke

Uncle Old Duke,

I see Virginia-state in its code states that when auto inspection station find fault with safety or emission, the inspection station is forbidden to perform the repair. So, a disincentive? Though the shysters probably have a work around ... the inspection station / repair facility that fails you has a recommended repair shop or three that can do the work "for a bargain" ... meh. Thank you.

In MO-state, just like Jersey as you describe. A real racket here. Legislation pushed and funded by the well-to do large families that own the new car dealerships. The used car market here, certainly after the wall street 'cash for klunkers' welfare (that junked many a fine RWD Volvo) has made the used car market very expensive for the buyer and profitable for the used car seller, dealer or private. Shysters.

I don't like the underdash works and wire harness of the 700-900. Yet can't be too hard to work through the wire harness and connectors & connections to ground) so aforementioned for the SRS. One wonders the 700 steering wheel clock spring equipped? Continuity checkin', that multimeter!

Happy Friday!

Earl Grey Tea & Hunny & Milk MacDuffed. Fancy 2% Milk this day.

hi kitty g- what you say is sad but true. surprised the pro shyster lobby here hasnt succeeded in saddling us with the inspection racket here in fla like in the states you mention. regards oldduke

Years ago, I had a similar problem with my 90 240DL. After much frustration, I ended up removing the SRS bulb from behind the instrument panel. Problem solved...:)

yeah, unfortunately the light needs to come on when you turn on the ignition.... so they know you arent cheating. been scheming on installing a time delay relay....
Thanks tho!

I'm really surprised that they even check that on a 1990!! Do airbags really have to be operational on a 27 year old car? When your car and my 90 240 were built the life expectancy for the SRS system was originally 10 years (since extended).

Here in Mass. they would never check that. Anything 2002 and older doesn't have to meet emissions requirements just a safety check...

well - that's what I've been told, but its a good point... maybe I'll see what I can get away with! Thanks!
Stu