Intermittent instruments

[kierant]

In the last week or so I've started to find that sometimes within minutes of starting the car (1984 6-cylinder XJ-S) the entire instrument pack stops displaying anything. Including all the gauges and the trip computer. All warning lights still work though. Sometimes switching the ignition off and on again will fix the problem, sometimes it comes back by itself, and mostly, it comes back at some point later in the day, i.e. by switching off and then waiting a good while.

I'm suspecting possibly a voltage problem from the battery because it's very old and either due to a fault in it, or a drain somewhere in the car which I've not yet found, it's run flat several times recently. Again though, intermittently!

So, I'll be changing the battery anyway. But does anyone have any other common pointers for where to look, perhaps for a dodgy connection?

[ptjs1]

kierant,

I'd give David Marks a ring and see if he can point you in the right direction. In case you weren't aware, the club pays him to provide technical support to members for XJS and other models.

My naive guess is that it wouldn't be just a battery problem. Although battery drain problems in XJSs can be a problem (boot light switch or alarms are often the cause) Intermittent loss of instruments doesn't sound like a typical XJS problem caused by a weak battery. It sounds as if there's an intermittent break in the whole feed to the instrument pack, particularly if the engine is running at the time of the problem. Maybe it's something as simple as the instrument pack connection plug being slightly loose?

Good luck with the investigation!

Paul