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[HOW TO] By-pass Neutral Safety Switch NSS

109K views 86 replies 38 participants last post by  Justus 
#1 · (Edited)
2000 SAAB 9-3 SE, Auto, 101k miles

Symptom:

Intermittently cannot start when car is hot (after driving). No crank at all, can hear fuel pump and one "click", all lights on instrument panel go on.

If wait for 15 mins to half hour, car will start up right away. Once the car started, it runs good. Never had problem with cold start.

The original post is here.

Tracking the problem:

1. Tested battery and alternator, they are all good.

2. Checked all the cables and terminals on battery, starter, alternator, etc. No loose nut, no corrosion.

3. Since fuel pump starts when the key is at "on" position and the car never dies when driving, the fuel pump should be fine.

4. It should not be the infamous Crank Position Sensor (CPS), since the car do not crank at all when the problem come. And it runs fine after started.

So, it is more likely to be the Neutral Safety Switch. There are many posts on SaabCentral and SaabNet regarding the NSS issue. Cost for NSS is $300 (parts) plus labor. It is very expensive. DIY for replacement is not very feasible because the room to work on is very limited. I was almost prepared to spend a couple hundreds to have it replaced until a few days ago I saw a post on SaabNet. The idea is that you can by-pass the NSS. It is pretty easy and cheap. Here is a step by step illustration on how to do it:

1.You need to take off the panel below the instrument panel. To do this, you will need to take the fuse box cover off first. There are three screws on this side, unscrew them.



2. There are three more screws and one bolt to loosen. The bolt is located on the left lower corner as indicated by the red circle.





3. Now look from beneath, you need to take the OBD II plug off. There are two screws. One is blocked by the OBD cover in the picture below.



4. With the panel off, you can see the relay box. There is one more screw to do.



5. A closer look. After taking off this screw, you can just slide the relay box off. There are four guide pins holding the box, you can see two of them in this picture.

 

6. Here is the relay box off. You need to take the "K" relay (the starter relay) out.

 


 


 
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#27 ·
Hey Coliphage- I tried the NSS by-pass with no luck, my 2002 9-3 would not start, just click at the starter. In your write-up you say to by-pass pin 30 & 87, but in your photo it looks like you used pin 86. Did I miss something? Even if the NSS was not faulty this by-pass should let the engine start right! I have a cel for the trans range sensor so if this by-pass didn't work (assuming I did it right) then I must have another problem in addition to the NSS!!
Any help is appreciated!

Matt
 
#50 ·
In your write-up you say to by-pass pin 30 & 87, but in your photo it looks like you used pin 86. Did I miss something? Even if the NSS was not faulty this by-pass should let the engine start right!
I was going to do this bypass on my 9-5. (not trying to hijack this thread, just clarify for myself & others) ;oops:

The relay is identical (the dash panel access is different however). When I look at the contacts on my car, and at Coliphage's excellent images, he's not connecting to the 87 terminal, it's the #86 he's attached to. #87 is top center, as you can see in the image. When you look at the relay diagram, it seeems to show that you should go 30 to 87 to bypass the relay, not 86.

So, has anyone else run into this when they tried this bypass? The only comment I see are by Matt C who noticed the 86 not 87 terminal. Not sure, should I actually go to the actual (as-shown) #86?
 
#34 ·
TROLLhattenschatten said:
I can hear the starter run. but it don't turn the engine.

When in park it does NOTHING i have to move it to neutral to get the starter to work, and even then it don't always engage the flywheel.
The NSS has nothing to do with the starter gear engaging the flywheel. If the starter turns the gear should spin out and engage the flywheel. While your NSS may be problematic it wouldn't cause the issue you describe in the first part of the above statement. However, doing "nothing" in Park could very well be the NSS.
 
#38 ·
FYI - in the pictures earlier, that's terminal 86 that's circled not 87. The picture is correct in which terminals to bridge with the switch, but the labels are wrong.

I just tried this on my 2000 9-5. It seems runs the starter now with the switch. Now the waiting game begins for the next NSS no-start. Tick tock..
 
#40 ·
Coliphaqe is my hero!!!!

Let's see, put a $300 switch into a 9-5 w/ 165K miles, or maybe try the bypass? Easy enough.

This is a fantastic bypass / fixit. I spent $5. This was on a 04" 9-5 Aero, and it was even easier than the 9-3 described by Coliphaqe.

Thank You! Thank You!!!:D:D:D:D
 
#45 ·
That is a genius solution :D
I'm currently going to do the NSS bypass as a test on the project car but was thinking about using another rear fog light switch placed upside down in the blank space under the fog light switch. Your method is much safer even though I'm just using this momentary switch as a diagnosis not a solution to the problem.
 
#46 ·
Hey man, thanks for the comment. Another problem that I see is the oil pressure switch seems to be closed for an oil pressure alarm. If pressure is present, the switch is open and - No alarm. Unfortunately, any open in the alarm system (including the sensor) fails to close and bring in the alarm. That's just like a fire alarm that closes to cause a fire alarm - what happens when something in that circuit burns open? No alarm... Ron
 
#47 ·
2001 9-5

This worked great on mine. Now there are other issues with my NSS, like not going into reverse from park but fine from drive. And after the car warms up the tranny goes into limp mode(it defaults to third gear only) and the gear light and check engine lights are on. So I bought a used NSS on Ebay. My question is, Can I keep the push start switch or will it mess up the replacement NSS?
 
#51 · (Edited)
Thanks for the AWESOME Tip. I just did the same myself and did a post on the 9-5 board since that what I drive. Basically the same as yours with a few minor changes.....posted some pics of my own. Biggest difference is I used a 20A push button Starter switch.

I went from 30-87 NOT 30-86 and it worked for me. I am still unclear if the picture is right or the the actual terminal numbers are right. If anyone can clarify even though I know this is an old thread I would appreciate it! If it needs to be 30-86 I need to go back in there and change it....

Super Solution!

post on 9-5 board:

http://www.saabcentral.com/forums/showthread.php?t=220318
 
#53 ·
Is it cranking over at all? Did you verify the relay was good? Did you wire to the correct Pins? If you have properly done this fix and it is not cranking then it is the relay or starter. I suspect you didn't get it quite right.......note, I used pin 30 and 87 which directly energizes the starter and does not go through the NSS wiring...
 
#54 ·
I've had the no start problem about 10 times over the last year so I'm thinking about going through this bypass over the weekend.

One question: after performing the bypass, do you start the car as normal (just using the key) and then ONLY use the push button when the car is not starting?
 
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