Instrument cluster swap, now SRS and ABS Light

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hutch
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Instrument cluster swap, now SRS and ABS Light

Postby hutch » Tue Jul 28, 2015 3:49 pm

A little while back I picked up a 900T vert (intro thread to come eventually...) that had its odometer rebuilt a few years ago and for some reason had a n/a cluster put in. In addition to a somewhat flaky fuel gauge I missed being able to see if it was actually boosting properly so I swapped in a new cluster but kept the same odometer so the mileage would stay the same. I was greeted with a SRS and ABS light when I started the car back up and was wondering if anyone had some ideas on why.

1. I also swapped in a new turn signal stalk, I was near the airbag connector but did my best not to even look at it wrong as I know it can trip the SRS light if the battery is still connected. I turned the wheel to get at the little bolt that holds the dash fascia on but no more so than I've done a hundred times before and have never broken the horn contact ring.

2. The horn does still work so I'm pretty certainly I didn't break anything.

3. The ABS light is steady and in briefly reading I've seen it suggested that a steady light indicates it is likely just a wiring fault and not an actual ABS system fault, which would blink. I was reading up on how to test the ABS codes but won't get around to that until this weekend.

4. The connector on the back of the speedo, is that at all related to the ABS system? I thought that was cruise control related and the cruise does still work but I just guessed as to which orientation it was supposed to have by the way the harness was bent.


Has anyone ever had a bad instrument cluster cause either of these issues? I'm thinking I'll first go back in through the speaker grill and see if maybe the right side connector isn't fully seated or the weird plastic coated printed circuit maybe got messed up but my next step will be to pull the fascia back off and swap back the original instrument cluster to see if that temporarily alleviates the issue. Any other ideas?

DeLorean
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Re: Instrument cluster swap, now SRS and ABS Light

Postby DeLorean » Tue Jul 28, 2015 7:17 pm

First off, did your old cluster HAVE both bulbs?

Second off, the SRS system is insane about faults. Once it sees a fault, you will always have the SRS light untill you re-set it with the tech 2 or Saab air-bag tool. These like to randomly come on if you do something like try to start the car with a low battery, or if you forgot to plug the gauge cluster in flipped the car to on, in that moment the SRS control unit saw no connectivity to the bulb, and now the light will be on as soon as it's connected again. Was the battery disconnected the entire time you had the cluster out? If not, I bet it's as simple as this.

If your horn is working, most likely the clock spring is OK. You just need to plug in the air bag tool, see why it thinks it's on, clear it, and see it it doesn't come back for the same reason.

The ABS system is not picky about the ABS light. If it has all it's sensor inputs, the pump runs when it should, and it has a good accumulator, the system will work, and you won't have an ABS light. Even if you have a bad accumulator, the system will work, but for the moment you step on the brake and the pressure props below minimum and the pump kicks on, you will have a brake & ABS light for a moment, but it will go off again as soon as system pressure returns to normal. You are probably going to find a dead or intermittent wheel speed sensor. Even a sensor that is intermittent, you won't have an ABS light when it's working and you will when it isn't.

In my 93 900-t I finally got me a good right front wheel speed sensor! The darn sensors are getting to be tough to find not all rusted into the hubs.

The connector in the back of the spedo is for the cruise control only. Even though the ATE ABS systems do have an output for a GM style cruise control unit, Saab didn't use it. When you roll around with the Saab ABS tool, you can see the MPH each individual wheel is seeing.
Less brake more gas!

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Crazyswede
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Re: Instrument cluster swap, now SRS and ABS Light

Postby Crazyswede » Tue Jul 28, 2015 7:54 pm

There is a light for sex reassignment surgery? Sounds akward.
I am the 73%

hutch
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Re: Instrument cluster swap, now SRS and ABS Light

Postby hutch » Tue Jul 28, 2015 8:51 pm

DeLorean wrote:First off, did your old cluster HAVE both bulbs?

Second off, the SRS system is insane about faults. Once it sees a fault, you will always have the SRS light untill you re-set it with the tech 2 or Saab air-bag tool. These like to randomly come on if you do something like try to start the car with a low battery, or if you forgot to plug the gauge cluster in flipped the car to on, in that moment the SRS control unit saw no connectivity to the bulb, and now the light will be on as soon as it's connected again. Was the battery disconnected the entire time you had the cluster out? If not, I bet it's as simple as this.

If your horn is working, most likely the clock spring is OK. You just need to plug in the air bag tool, see why it thinks it's on, clear it, and see it it doesn't come back for the same reason.

The ABS system is not picky about the ABS light. If it has all it's sensor inputs, the pump runs when it should, and it has a good accumulator, the system will work, and you won't have an ABS light. Even if you have a bad accumulator, the system will work, but for the moment you step on the brake and the pressure props below minimum and the pump kicks on, you will have a brake & ABS light for a moment, but it will go off again as soon as system pressure returns to normal. You are probably going to find a dead or intermittent wheel speed sensor. Even a sensor that is intermittent, you won't have an ABS light when it's working and you will when it isn't.

In my 93 900-t I finally got me a good right front wheel speed sensor! The darn sensors are getting to be tough to find not all rusted into the hubs.

The connector in the back of the spedo is for the cruise control only. Even though the ATE ABS systems do have an output for a GM style cruise control unit, Saab didn't use it. When you roll around with the Saab ABS tool, you can see the MPH each individual wheel is seeing.
Thanks for the insight, as always...

Yeah the old cluster had the bulbs, they powered up as usual and went away once the car was started. Thats why I figured it had to have something to do with the new cluster, unless I messed something up with the turn signal stalk swap. To further complicate things the low battery light was on when I started it up to drive home tonight and I saw the rear brake lights stick on shortly. Maybe they were stuck on and drained the battery enough to trip the light :dunno:

The SRS light I'm not super concerned about, my eventual plan is to take to the local Saab shop and have them clear the code. If it comes back, I'll register it as an antique and pull the bulb :lol: I'm more concerned with the ABS light since I'd like to actually have the brakes work, that I'd rather not just pull the bulb. I've always wondered if you could drain the capacitors of the SRS ECU to reset it, that is at least how I work on old guitar tube amps without electrocuting myself. :lol: But its probably easier to just get the local shop to reset it and not mess with it too much...

The only thing I can think of is I dropped a socket extension down the drivers side fender while removing the lower kick panel, maybe I hit the wheel sensor lose or something while retrieving it but I doubt it. I'll definitely check those too as one of the front brake pads is squeaking so I'll probably be in there sooner rather than later. I will say the brake lights had stayed on for 10 or so seconds after startup, like several of the ABS c900's I've owned, so maybe the accumulator is getting old but it always went away before the instrument cluster swap.

Good to hear the speedo cluster connector was cruise control only, thats what I figured but when I had to guess which way it went and the ABS light popped up I thought I should at least check.
Crazyswede wrote:There is a light for sex reassignment surgery? Sounds akward.
Its the big E! light on the dash :lol:

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DeLorean
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Re: Instrument cluster swap, now SRS and ABS Light

Postby DeLorean » Tue Jul 28, 2015 9:37 pm

I jumped my 92 900 4 door after letting it sit for probably 2 months with a dead battery, and bam. SRS light. I know for a fact that there are no faults because as soon as you keep a charged battey in it and re-set the light, it stays out.

On an unrelated note, I nearly got to use the SRS system in my 93 900 about 4 days ago! I was coming over a rise that's always clear on the other side, get a little bit of air and brake hard for the corner. Well.... apparently someone was turning left in the "limited sight distance" zone AND there was on-coming. In my lane, 4 cars were packed up behind it stopped. I came over the rise, and went into full panic stop mode when I saw the situation. Lets just say it's a darn good thing there was a field to my right, I ended up using it. No damage, but I want my ABS to work after that... If the situation had been different it could have been very bad. I am going to slow down over that rise for the future.
Less brake more gas!

hutch
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Re: Instrument cluster swap, now SRS and ABS Light

Postby hutch » Wed Jul 29, 2015 3:56 pm

DeLorean wrote:I jumped my 92 900 4 door after letting it sit for probably 2 months with a dead battery, and bam. SRS light. I know for a fact that there are no faults because as soon as you keep a charged battey in it and re-set the light, it stays out.

On an unrelated note, I nearly got to use the SRS system in my 93 900 about 4 days ago! I was coming over a rise that's always clear on the other side, get a little bit of air and brake hard for the corner. Well.... apparently someone was turning left in the "limited sight distance" zone AND there was on-coming. In my lane, 4 cars were packed up behind it stopped. I came over the rise, and went into full panic stop mode when I saw the situation. Lets just say it's a darn good thing there was a field to my right, I ended up using it. No damage, but I want my ABS to work after that... If the situation had been different it could have been very bad. I am going to slow down over that rise for the future.
Hmm well here's to hoping that it was just a discharged battery that caused it to trip the light. I'm hopefully going to pull the ABS codes this weekend from under the seat and then hopefully get an appointment to get the SRS code reset.

Sounds like a scary situation, I'm always curious why more people end up rear ending the car in front of them instead of pulling off the road since so much of PA has a 'oh shit' patch of grass on the sides of the road. But I guess most people don't have much time to think in those situations :dunno:

But yeah thats why I'm much more concerned with the ABS light than the SRS, I feel the ABS will be much more useful in an emergency situation.


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