Battery dying after clutch switch bypass

[PandaSPUR]

So I've had issues with my clutch switch for a while now, its already been replaced once and the second one really started to become a consistent issue after this past winter.


Still cant manage to replace the damn switch myself and dealer wanted to charge 150 just to diagnose. Wouldn't tell me how much the actual swap would cost -_-


Decided to just bypass the switch for now by using a little wire with two spade connectors, inserted into the plug for the switch.


Since then, my car's battery keeps dying after 1-2 days. I thought maybe I bumped something down there when I was working but I can't think of what it could be.


Why would bypassing the switch actually cause the battery to drain? I'm wondering if its because I leave the car parked in a valet operated garage... they keep the key on the dash after parking the car.


Tried googling this... everything I find says the switch bypass shouldn't cause any battery issues. Maybe its different since I have the push button start, so key in cabin + switch bypassed = car always thinking its about to start?

[Mr.ac]

If it was my guess, (and this was after reading the manual) it's leaving the key in the car.

[PandaSPUR]

Originally Posted by Mr.ac

If it was my guess, (and this was after reading the manual) it's leaving the key in the car.

Well, it would be leaving the key in the car AND having the switch bypassed. I've parked at this garage for over a year now and never had an issue with the battery dying cause the key was in the car.


Ordered a set of thin metric wrenches from amazon.. hopefully I'll be able to get the god damn switch out with those.

[geraldjust]

Originally Posted by PandaSPUR

Well, it would be leaving the key in the car AND having the switch bypassed. I've parked at this garage for over a year now and never had an issue with the battery dying cause the key was in the car.


Ordered a set of thin metric wrenches from amazon.. hopefully I'll be able to get the god damn switch out with those.

Is it a push start or turn key?

[tobin]

Original battery in your '15? It could have just finally given up the ghost. Stock batteries last like 2 months.

[geraldjust]

@PandaSPUR

IF your car is a push start the moment the clutch swtich get to depressed position it wakes up the Certification ECU, That then sends a can signal to other modules in the car (BCM) to get ready to turn on. So a bunch of computer modules wake up. and they only go back to sleep after 20 seconds of the clutch not being depressed. (when the car is off)

So there is your problem. Maybe if your out in the "delivery" fuse thats under the hood in place could minitage a bit this issue, but i dought it.

[PandaSPUR]

Originally Posted by geraldjust

Is it a push start or turn key?

Push start

Originally Posted by tobin

Original battery in your '15? It could have just finally given up the ghost. Stock batteries last like 2 months.

I considered that because yea, it is the original battery, but the timing would be pretty coincidental.

Originally Posted by geraldjust

@PandaSPUR

IF your car is a push start the moment the clutch swtich get to depressed position it wakes up the Certification ECU, That then sends a can signal to other modules in the car (BCM) to get ready to turn on. So a bunch of computer modules wake up. and they only go back to sleep after 20 seconds of the clutch not being depressed. (when the car is off)

So there is your problem. Maybe if your out in the "delivery" fuse thats under the hood in place could minitage a bit this issue, but i dought it.

That would explain it. I kinda suspected that + the car being a push start + the key being left in the cabin was probably the main issue. Sigh, guess I really need to try fixing that switch myself ASAP or just paying a shop to do it.

[geraldjust]

Originally Posted by PandaSPUR

Push start






I considered that because yea, it is the original battery, but the timing would be pretty coincidental.






That would explain it. I kinda suspected that + the car being a push start + the key being left in the cabin was probably the main issue. Sigh, guess I really need to try fixing that switch myself ASAP or just paying a shop to do it.

YEP! well that's the issue. When you store it for long term try to see if you can use a battery tender. OR put the delivery fuse in the proper place before long term storage. Could help if you fix the clutch switch. lol

[PandaSPUR]

Managed to finally swap my clutch switch using a set of ultra thin wrenches (https://www.amazon.com/gp/product/B001PTF9MY).


For anyone curious, this is what the inside of one of these stupid switches looks like:



And see these dots on the actual contact points? Looks like this is how/why the switches stop working... Those dots (corroded points?) are not conductive as I confirmed with a multimeter

[Ultramaroon]

Don't show this to @Sapphireho. He doesn't believe in taking things apart to see how they work

[Ultramaroon]

Been thinking about this and studying the wiring diagram. Would you say it's possible that you let go of the clutch as soon as the engine fires? More importantly, before the starter circuit times out on its own?

I can go into a more detailed explanation if you're interested.

[PandaSPUR]

Originally Posted by Ultramaroon

Been thinking about this and studying the wiring diagram. Would you say it's possible that you let go of the clutch as soon as the engine fires? More importantly, before the starter circuit times out on its own?

I can go into a more detailed explanation if you're interested.

I suppose its possible, but its not like I'm ever in a rush to let go of the clutch during ignition.


Whatchu thinking? Some kinda arcing causing the switch to degrade?

[Ultramaroon]

Originally Posted by PandaSPUR

I suppose its possible, but its not like I'm ever in a rush to let go of the clutch during ignition.


Whatchu thinking? Some kinda arcing causing the switch to degrade?

Yes. I can see in the wiring diagram that the switch is in series with the start relay winding and ECM. In this case, the energy that causes the arc comes from the collapsing magnetic field in the relay winding. The ECM has components built in to absorb that pulse when it lets go of the relay but they don't do anything to protect the arc from forming across the switch when it opens the circuit first.

[PandaSPUR]

Originally Posted by Ultramaroon

Yes. I can see in the wiring diagram that the switch is in series with the start relay winding and ECM. In this case, the energy that causes the arc comes from the collapsing magnetic field in the relay winding. The ECM has components built in to absorb that pulse when it lets go of the relay but they don't do anything to protect the arc from forming across the switch when it opens the circuit first.

Interesting find... So if I keep my foot on the clutch longer (i.e. keeping the contacts together) then I can let that energy pass between the contacts without the arc, thus increasing the longevity of the switch?