I was driving this evening going around 20mph. Then I hit a big pot hole on the passenger side, right after that the car beeped and turned off. No warning lights came on. Right after that the car wouldn't start I thought I did some great damage. No warning lights came on just like radio and interior dome light. So I knew it wasn't the battery. I searched a little and read about the inertia switch, I eventually found it pressed it. Then the car started! So my question is could the inertia switch make it so the car wouldn't even crank? I thought I had a loose ground.

 

I am assuming an X300 ?????.

Not sure what it kills on mine, never tried it.

On the XJ-S it kills the fuel pump circuit. The S2 XJ12 does the same, and also the starter circuit, not sure if that is by design or just old age.

I reckon you got other gremlins, but if its running and doing what it should, dont mess with it.

 

I hope I do not have any gremlins. When I got home I restarted the car and it did start up. One thing that was odd was when the car wouldn't start when I put on the headlights only the passenger side light would come on. When I hit the high beams then they would all come on. Then after I pressed the Inertia switch both lights came on

 

Bugga, I need a drink, so do you.

The inertia switch has NOTHING to do with headlights, full stop.

I would start by checking some earth wires, and the main battery cable connector at the +ve battery terminal.

Something else is loose, and caused those outages.

Reading my handbook and other stuff I got, the inertia switch is "fuel circuit safety OFF", which was my thoughts in the first place.

 

The inertia switch kills fuel pump and yes a pothole or a wheel weight coming off the wheel will trip the inertia switch

 

I drove again today and the car drove normal.

 

I'm betting the headlamp is intermittent and will fail completely soon,