multiple intermittent electrical faults

[tonatcher]

hi everyone, my first post.
I have a 53 plate z4, really great mechanically and totally rust free, but electrics are something else. So far, wipers just stop or won't park, central locking failed( ordered new relays ) then just started working before relays came. open roof release stuck intermittent, fuel filler won't always open (drive around and come back) OK! Although mpg etc display works it does noy show data? ETC ETC
Is there perhaps a recognised dodgy ground point on this car that could be responsible?
Regards Anthony

 

[smorris_12]

The wipers is probably grease all over the position sensor tracks in the motor; quite common.

The rest does sound like a dodgy earth. I'd start with the battery connections. I'm not sure if there's a traditional earth strap from block to body.

One other thought is that it could possibly be a fault with the instrument cluster. It's quite central to control of things and the fact that the mpg display isn't showing anything makes it sound a bit comms error. There was a thread a month or so ago where that was the root cause of gremlins (tho I forget details.)

 

[tonatcher]

Thanks Scott will have a look.
Cheers

 

[DMike]

Sounds systemic. If you have access to a scanner, reading the error codes would also help to orientate. Battery connections or failing battery should give a number of undervoltage errors, in addition to causing gremlins here and there. A dodgy module flooding the bus traffic could also interfere with several systems.

 

[enuff_zed]

No electrician but agree with all the above.
1. Get all the codes read, then reset and see which ones come back.
2. Clean the wiper motor as that is a common issue, and will also give you a chance to clear all the debris under the scuttle panel and clean the drains out.
3. Central locking could possibly be a GM5 module on its way out if it's not part of the bigger problem.

Definitely do one thing at a time, then recheck what is still wrong, preferably with another code read.
Whilst grabbing several straws at once may fix the issue, you will never know what did it and if it fails again later you won't know which one to go to first.

And please, if you have time, keep this thread running to itemise each step and its results. It will educate the rest of us and potentially bring up a light-bulb moment for someone to help you sort it all out.

Whereabouts are you, as there may be someone close by with access to a code reader, or some of the fancier diagnostic software, that could help you.

 

[enuff_zed]

Oh and by the way, if it does turn out to be an instrument cluster issue then speak to [ref]bigwinn[/ref], who has just this month worked out how to replace them and keep all your car's info in the new one.