Strange intermittent electrical faults - Solved!

[Danusername]

Hi all,

A few months ago I bought a 2018 R, and it was great for the first couple months. Since then it has developed and odd electrical issue, where the dashboard will flicker the AC fans will turn on and off etc. (it only does this at idle).

I have replaced the battery, and cleaned and reconnected the rusty wheel arch junction. Cleaned and reconnected the ground wire between the body and the starter motor.

The car supposedly has a Scorpion immobiliser fitted, but on a whim I took the battery out of the fob and the car still started, so I'm wondering if that's playing a role.

I'm not sure what to try next, any suggestions would be greatly appreciated.

Thanks!

[Billymcmred]

Did you buy the car from a dealer ? If you did check out your consumer rights guessing by what you say about immobiliser it was already on the car if it’s not working contact the dealer

[Danusername]

Thanks for the reply,

I did get it from a dealer(not jaguar, just general used cars), they are a 2 hour drive away though. So id rather just fix the issue if I'm able.

Consumer rights says I get 6 months for recourse though, so ive got 3 months left if it really comes down to it.

It feels like it must be some sort of poor or loose connection somewhere.

Ive read there can be a corroded ground strap to the transmission bell housing, I wasn't able to see it when I was under there the other day though. Do you know where that is?

[Andyp123]

You don’t need to drive 2 hrs to the dealer. If you have a warranty on the car your dealer should be able to arrange for a local Indy near you to take look get a diagnostic then they should sort the issue via your warranty with your local Indy. I had a number of issues on my 2019 car over the 6 month warranty and my garage was brilliant I didn’t pay a penny for the following sos issue on dash, faulty fuel injected, replacement of exhaust valves.

[scm]

Random electrical gremlins usually point to low battery voltage - is it possible your immobiliser is putting an excessive drain on the system? If you can, try giving the car an overnight charge and see if the problems go away (every night to make sure!).

[Danusername]

Thanks for the reply scm, i have been looking high and low for the immobiliser box. It just doesnt seem to have one?? Pulled the trim off around the steering coloumn, looked around under the glovebox, in the engine bay around the ecu nothing :s

I have also now replaced the alternator, it didnt help at all.

Im finding during testing that the flickering fault appears after around 5-8 mins of idling. Where the engine reaches its slowest rpm. The voltage at the battery changes from 14.7V down to between 12.5 and 13 when this happens. Im wondering if some module is on the blink now.

I have the battery charging outside the car now, it was at 12.5V when i started charging it. We shall see if that does anything

[DanL]

Check for a loose ground cable connection on the negative battery post. It's a very common problem even when the battery ground cable bolt has been fully tightened. See if you can rotate the cable on the post by hand. If you can, purchase a battery post shim cap to solve the problem.

[Danusername]

Thanks to everyone who tried to help with replies. I found the problem was a terribly fitted (but well hidden) aftermarket immobiliser. Pulled that out (wasn't even soldered in), wrapped the cut insulation and was sorted!

[gasgas]

result

[Billymcmred]

Thanks to everyone who tried to help with replies. I found the problem was a terribly fitted (but well hidden) aftermarket immobiliser. Pulled that out (wasn't even soldered in), wrapped the cut insulation and was sorted!

Nice