I have been chasing an intermittent no start in my xjs for over two years. I've been through 3 jaguar specialist mechanics in 2 states and several misguided repairs. The car may start and then not start and so on several times in a given day or even over the course of a few minutes. When the car doesn't start the signal never gets to the starter, it doesn't turn over at all. I CAN start the car by jumping the wires at the relay with the key on. I have replaced the relay and its not the issue.

I have a similar intermittent problem with the automatic top down mechanism for the convertible top. Sometimes it works, sometimes it does not. I have recently noticed that these things coincide. When the top works the car starts, when the top does not work the car does not start.

It occurs to me that both starting the car and using the automatic top require the car to be in park (or neutral for starting). So I am thinking my next suspect is the neutral safety switch. Apparently this part is not available. Can it be bypassed entirely? I would prefer to just have both systems work regardless of the gear selector.

Also, I must admit I don't even know where this switch actually is. this picture is of my gear shifter. Is the switch the round thing on the side or the 4 connections on the top portion?


Thank you all. This battle must be won.

 

The neutral switch is the white connector with the black/green wire. The other switch with the yellow/red wire is for cruise.

The switch can be bypassed, just ground the black/green wire. That means the starter will engage in any position of the gear lever, not just P or N. The switch is a simple microswitch, I'm sure you could find something similar at an electronics supplier such as Digikey.

So it's a case where the car will start if it cranks, but it doesn't always crank?

 

You got it. If the starter cranks the car will start.

 

It's a very simple circuit, it's either the ignition switch itself, relay or the neutral switch. I'd start by grounding the black/green wire and see what happens.

Those switches were used on the Series 3 sedans as well, so if you see one at the junyard you could grab a switch to try.

 

Pretty easy to ground it too. There's a perfect chassis ground to the left of the radio.

 

It is for sure the microswitch or the ignition switch. Very likely the microswitch is a touch out of adjustment. make sure it is actuating definitely in park and neutral.
Greg

 

Thanks guys. I will address it this weekend. If this solves this issue I will be drinking to you all.