NG 9-5 Earth points

[GeoffR]

It is well known that a number of modern cars can be very unforgiving of low battery charge conditions. The NG 9-5 is, apparently, not exempt from this problem.

One reason for the system to generate fault messages is high resistance in sensors and load components, motors, solenoids and lamps. While doing a routine check round the engine i decided to check the earth points, these are located around the front strut top mounts and on the bodywork between the radiator and the headlights. I also checked the battery earth connection.

Contrary to popular belief the battery terminals should be absolutely free of any contamination during assembly. By all means apply a thin film of suitable grease after assembly. The quoted torque value for the battery terminal bolts is 4.5 nM not 20nM both terminals were well below the WIS figure when I started.

Earth points similarly should be free of all contaminants when assembled, I disconnected one to find that this wasn't the case so I cleaned the earth point, ring terminal and nut before tightening it, I used 15nM. I checked all the other earth points and found the torque to be well below this figure.

Whether you are suffering from spurious fault messages or not, I would urge all NG9-5 owners to check the tightness of all the earth points and the battery terminals.

[GeoffR]

Having posted the above I paid another visit and took some photographs.
Note that one of the earth points that I found loose was the main body earth, where it connects to the battery. Obviously a loose connect here will affect everything electrical on the car.



The other image shows the earth points at the front strut top mount.



I hope this will help somebody to prevent an unnecessary trip to the dealer. It may even mean that you don't replace a perfectly good battery.

[nordwulf]

I moved this over to the 9-5 NG forum as that's where most of the 9-5 owners hang out. But there is still a link in the Tech Talk forum where is was originally posted as this an issue that can be important for any Saab owner.

Thanks for the write-up and pictures.

[GeoffR]

I moved this over to the 9-5 NG forum as that's where most of the 9-5 owners hang out. But there is still a link in the Tech Talk forum where is was originally posted as this an issue that can be important for any Saab owner.

Thanks for the write-up and pictures.

Thanks, I am working on a fuse chart and I may need some help, if anyone has a Diesel NG9-5 please get in touch.
The handbook gives location and function but doesn't give fuse values, my chart will have both but, as mine isn't a Diesel some of the fuses are missing so I don't know the ratings.

[nordwulf]

There is a complete chart with fuses, their location, schematic and ratings in the Saab WIS. I can post that if it helps you out.

Example:

X51A Fuse Block - Instrument Panel - Usage Fuses

No.	Device Name	Device Assigned Name	Rating	Description
1	1	F1DA Fuse	10 A	K19 Suspension Control Module (F45)
2	2	F2DA Fuse	20 A	K9 Body Control Module
3	3	F3DA Fuse	25 A	K9 Body Control Module

[GeoffR]

I have a copy of WIS so I will have a look but I haven't found the chart yet. I am also intending to provide more useful information, there are four fuses with the description "Body control module" which I assume are actually functions controlled by the module rather than power sources for the module.

[nordwulf]

Fuse and relay info in the WIS is at: 3. Electrical System - Wiring harness and components - Electrical Center Indentification Views

[GeoffR]

Fuse and relay info in the WIS is at: 3. Electrical System - Wiring harness and components - Electrical Center Indentification Views

Thanks, found the right page, now to make it into useful data.