Hi all, thought I would add my findings to the thread, great pics BTW.
I have been having problems with the Air-Bag light for some time. When it first happened I had a look at the codes (I have a Honda HIM and Honda software running on my car-pc) and it identified the Driver seat belt sensor.
I’m in no position at the moment to go down the dealer path and as I was removing the seat for another project, I decided to take a look at the buckle.
This condition had been getting worse and if I watched the lights closely I noticed that every so often the seat belt indicator was not coming on as the seat belt was released. I was interested to see if the metal actuating slide that drives the micro-switch lever could be binding in any way.
Well it wasn’t, and the Micro-switch lever was not bent or fatigued. Micro switches normally have a definite click as the internal spring loaded switch flicks between the two contacts and this is independent of how fast or how far the actuating lever travels, it just has to move and release enough to allow that action to happen. The switch action occurs over a very small amount of the total lever travel. FYI the switch in this unit is a double throw single pole, IE A changeover switch.
Testing on the bench proved it to be working faultlessly in both directions. One of the tests I did before removing from the vehicle was to slowly withdraw the belt from the buckle, I could get it to fault more often than if I ejected it quickly, again, that’s strange if it’s just a switch contact problem as in a micro switch, the internal changeover speed is not affected by how fast you move the lever.
I think there is a possibility that in my case, the sealed plunger which is driven into the switch by the lever may have been binding. I read somewhere of the red sealing ring being levered out with a pin and someone spraying cleaner into the micro-switch (ruined the seal). However it may have just been the rubber/plastic sealing ring that was the problem after all.
I was not going to do anything to the switch that could affect a possible lifetime replacement policy (haven’t had a straight answer on that over here as yet) so I simply sprayed the shaft with a special contact cleaner and switch lubricant (one that leaves no residue for dust to adhere to and is plastic friendly). I also sprayed/cleaned the under seat plug and socket as I had read of intermittent problems there as well. Assembled and back in the vehicle and it’s been perfect for the last few days, it will be interesting to see how long it holds up.
I’ve serviced various equipment running high cycle “sealed” micro switches and over time I can’t really remember having to replace them for an intermittent switch contact, they either worked or they didn’t, anyway, I thought this may be of interest to someone.
BTW, the micro switch and lead assembly just pop out, carefully though, it’s a plastic locating tab on the switch that locks into a metal spring clip/retainer.