Driver Seat Airbag Repair

GTE · 27-08-2013 12:45pm #1

Hello!

I own a VW mk4 Golf. A common problem with these cars is where the plug underneath the seat for the front seat airbag causes intermittent signal loss and an airbag warning light.

Having fixed it a year or so ago with a solder connection, the light has come back on. I am concerned that there is now something wrong with the airbag itself and that the plug repair was a false alarm, but still a good thing to do. I keep clearing the codes (which is a driver side resistance code) and they are coming on every few days.

Does anyone know how costly it would be to replace the drivers seat side airbag? The car failed the NCT because of the airbag light when the tester moved the seat all the way forward. I checked the connections and cleared the code for the retest and thankfully it didn't come back on immediately but a week later I went around a round about and it came back on.

I could do that or get a new front seat, but I can't seem to find individual ones with lumbar support which is a prerequisite for any new seats or cars for that matter.

Many thanks!

Dublinstiofán · 27-08-2013 11:08pm

Having similar problem myself booked in to have it looked at next week.

mickdw · 27-08-2013 11:16pm

Its still the wiring under the seat at fault if the act of moving the seat set off the light.
Did you solder all the airbag connections?

Dublinstiofán · 27-08-2013 11:42pm

I took the seat out and had a look for the connector that is to be soldered (tutorial) but that connection is not under my seat.

The fault with mine is resistance in the wiring. Fault code on mine is N200 'Resistance too small'
have to bring it in and get it looked at.

GTE · 28-08-2013 1:57am

mickdw wrote: »

Its still the wiring under the seat at fault if the act of moving the seat set off the light.
Did you solder all the airbag connections?

Yes, I fixed it by soldering around a year ago. It may be the wiring under the seat acting upon the connection of the airbag at the airbag itself at the side of the seat or a general fault with the airbag itself that has fooled me into thinking it was the plug by showing similar symptoms.

Dublinstiofán wrote: »

I took the seat out and had a look for the connector that is to be soldered (tutorial) but that connection is not under my seat.

The fault with mine is resistance in the wiring. Fault code on mine is N200 'Resistance too small'
have to bring it in and get it looked at.

I had this fault on the passenger side seat airbag and that gave a resistance related error. The current problem is a resistance error too, though I can not confirm what the hell is going on. I did the solder fix on the passenger side and I have had no problems since.

The reason I say that is because that how to looks very different to my car. You must have some cable running from the floor into the seat to get to the airbag, if we are talking about the same generation of car. You could jump the gun by bringing it somewhere if you havent tried the solder fix yet.

dh0011 · 28-08-2013 2:03am

might be worth getting a seat from a scrap yard. You might be able to remove the fabric and soft stuff from your own seats.

GTE · 28-08-2013 2:31am

dh0011 wrote: »

might be worth getting a seat from a scrap yard. You might be able to remove the fabric and soft stuff from your own seats.

I will look into what would be required to do a complete swap onto a "new" seat, could be a big job. It would save on getting a full new interior or waiting to find the same model of seat. That said, finding a single leather drivers seat with the rest of them being cloth would show the passengers who is boss hahaha

I think I would have to make sure it had lumbar support, maybe the ones without would still have the holes required. That could almost be the best way because the seat is beginning to creak anyway.

carefull now! · 28-08-2013 7:35am

There are usually two connectors under each seat, one on the seat, one in the floor, bypass both of these with new wiring and you should be fine. After that you'll need to replace the airbag

GTE · 28-08-2013 4:19pm

I checked under the seat and the solder is still fine. I have since checked the fault code and it went from being "Side Airbag Ignitier; Drivers side (N199) Resistance too high (intermittent)" which would happen every few months to few weeks to it being too high permanently.

The fault appears immediately after it has been cleared. Block 5 of the airbag module in VAGCOM says its too high. I think the exact fix in VW garages is to splice a further 3 inches of wire when cutting out the old plug.

I didn't do this, but I would have thought if I did now that the resistance would be higher still.

I don't see a plug under the carpet in my 2000 Golf so I am stumped from a DIY point of view and concerned that it is a new airbag required.

EDIT:
Now that I say that, moving the wire harness under the drivers seat while monitoring block 5 has given me a correct resistance so further fiddling required.

Fingers crossed!!!

GTE · 28-08-2013 4:37pm

I might just call this a success.

A VW tech which spoke on other forums said that the wires should be twisted together after soldering. I am assuming this is to ensure that the collective effect this would have on the resistance would remain the same as it would be before the plug was removed.

I guess I didnt do a good enough job at that. With everything more or less still stuck together, I took the slack in the harness and made a loop. This is the closest pic I could find. Just imagine the piece of metal holding the loop together is electrical tape.

This has stablised the resistance reading and after some manhandling of the harness, bashing it around the place, the resistance has remained "correct".

The important point to note out of all this is that the ECU is expecting an exact resistance reading, and DIYers who are saving some cash to fix a problem with the plug need to do what they can to ensure the resistance remains the same.

It seems like it is a rare case when these things go wrong as so many people have had success with the DIY and my passenger side seat with the same fix applied doesnt need this extra bodge that I just had to do.

That all said and done, expect a post from me soon saying that the airbag light is back =( =P Murphys law!

the airbag man · 31-08-2013 1:22pm

airbags fall in resistance with age, the mk.4 started in 1998 and ended in 2004
so your car is between 15/16 and 9/10 years old, even at 10 years of age it is 3/4 years in the danger zone, hence why the car manufacturers recommend replacing all airbags after 6/7 years of age. look at the inside area of the left sunvisor of any honda.
1. gently dig into the airbag from the back of the seat and you will see the cover comes off quite easy from the bottom up,
2. with a ohms meter set to multi ohms take reading direct from the seat airbag just where the plug meets the bag, it should read between 2.5 and 3.2 ohms.
3. once you have carried out stage 2. take a reading at the end of the seat wiring loom where it would marry the cars main wiring loom, if its not giving you what it should be in stage 2. then you will know if its the airbag or the seat wiring loom.
the same gos with the car main airbag module, in the same age period the memory chip in the module gets weak.
carry these checks out with the ignition switch in off.
if still in trouble pm.

tossy · 31-08-2013 1:38pm

I've just twisted them together in the past and covered with heat shrink,and had zero issues. Soldering messes with the resistance,especially crap soldering (the type i do)

Driver Seat Airbag Repair

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