p38 tailgate button internal spring

[Grrrrrr]

Until the week before last I had the P38 poltergeist that traveled with me on every journey. Bumps in the road, drivers window operation would result in all doors being locked and unlocked. It even did it while sitting unoccupied on my driveway while I was working in my workshop.
My first stab at a fix was putting a jog-unit on 317Mhz in the car to prevent the P38 RF-Unit bug from striking. The Jog-unit was £7 compared to £200+ for a new RF unit. It was a partial success but the battery still dropped volts faster than I would like.
Then I changed the drivers door-latch (which changes all the switches) problem gone!
I have been monitoring my battery voltage since the change and it appears to me that the old-latch and switches must have been drawing more current at various times because now I don't get a weak/flat battery indication after 18 to 36 hours of being parked up and locked closed. YMMV and your Poltergeist may need the intervention of a priest or some other person with powerful Ju-Ju.

I think it is the centre microswitch on the lock actuator that grounds to open the tailgate. Although it only does it briefly it does seem to pull a lot of current through a little switch. Over the years that eventually tells. Marty upgrades them when he replaces them.

 

[DanClarke]

I think it is the centre microswitch on the lock actuator that grounds to open the tailgate. Although it only does it briefly it does seem to pull a lot of current through a little switch. Over the years that eventually tells. Marty upgrades them when he replaces them.

I've seen the "how" of it and quality switches are pretty cheap so I wonder where LR sourced their's from.
Not only that but they are rated for 6A @ 240v for 10,000 operations and that's a lot of AMP capacity when only 12V is in the equation so they should never fail again.

 

[Datatek]

I've seen the "how" of it and quality switches are pretty cheap so I wonder where LR sourced their's from.
Not only that but they are rated for 6A @ 240v for 10,000 operations and that's a lot of AMP capacity when only 12V is in the equation so they should never fail again.

I'd bet that the 6A @ 240v is for AC. DC is a whole different ball game, even at 12 volts arcing when the contacts open can be a problem and that is what knackers the switch.

 

[DanClarke]

I agree its a whole different ball game, but 240V @6A is a potential for 1440Watts to be dissipated in a discharge (worst-case) and for 12V to have the same wattage dissipated wouldn't this be 120Amps?
I didn't think the circuit drew much more than 30A, so seeking to arc 360 Watts. But hey, I agree DC & AC are different for sure. I was hoping to simplify it on a WATTS power basis and was therefore assuming the DC would be less aggressive as it was likely to be a much lower wattage.

 

[Datatek]

I agree its a whole different ball game, but 240V @6A is a potential for 1440Watts to be dissipated in a discharge (worst-case) and for 12V to have the same wattage dissipated wouldn't this be 120Amps?
I didn't think the circuit drew much more than 30A, so seeking to arc 360 Watts. But hey, I agree DC & AC are different for sure. I was hoping to simplify it on a WATTS power basis and was therefore assuming the DC would be less aggressive as it was likely to be a much lower wattage.

DC is more aggressive, look at the specs, almost all switches are dramatically de-rated for DC. Watts really do not matter, the nature of the load does, any poorly damped inductive load on DC will rapidly destroy the contacts. Back EMF on 12 volts from an inductive load can easily produce several hundred volts resulting in an arc.

 

[DanClarke]

DC is more aggressive, look at the specs, almost all switches are dramatically de-rated for DC. Watts really do not matter, the nature of the load does, any poorly damped inductive load on DC will rapidly destroy the contacts. Back EMF on 12 volts from an inductive load can easily produce several hundred volts resulting in an arc.

Cheers @Datatek

 

[tomcat59alan]

We are experiencing a parallel universe .