Hi Guys,

Am after a wiring diagram or advice regarding electrical issues i am haviving with my 2008 GTC.

The issues i think are all related to one common cause, the problem arose last week one night when i was going out in the car, (it had been perfectly ok in the morning).

I noticed that i had no lights or display on my dashboard, none of the gauges work (rev counter,fuel,temp etc) the clock will not adjust automatically to the correct time.

Since then i have also discovered electric roof, air con controls, heated seats, suspension controls also don’t work, maybe other items that i have not discovered yet.

I have scanned the car with my launch x431, and it comes back with cant communicate / implausible signal with all of the above control units.

Both batteries where replaced Dec last year, i have checked them with my Launch tester which shows the as good, mega fuses on the battery have been tested and also fine.

Battery terminals have been checked, cleaned and tightened, as have the visible negative connection to the body.

So my cry for help to you all is, is there another main fuse somewhere?, do you think it is all to do with the same problem?.

I assume these are all controlled by the house battery (big one), the batteries are never allowed to go flat as they have a small CTEK charger connected when the car is not in use.

Is possible that the house battery, although it shows 12.9 volts and when tested showed good, has a amp storage issue hence not having the power to supply everything.

I have also had the battery on charge with my big CTEK unit (ground was disconnected), but after 15 minutes it showed the battery had full charge.

Am sure somebody must have had this issue before and can please point me in the right direction.

Bob

 

Bob,
Apparently you’ve got company. 2008 GTC. Replaced the housekeeping battery 2 weeks ago because it appeared to be having issues holding a charge. Had the car out last Saturday and drove it a fair amount. Generally hook up my Ctek charger but was going to take it out on Monday so didn’t bother. Monday morning the car was completely dead. Nothing was left on. Put a Full charge back on the house battery and when I checked the car on Tuesday the instrument cluster was completely dead. Was also hearing some audible pops from the back speakers like there was some amp still on. It does have the Pioneer 4500NEX head unit installed. I’ve only had the car for about 3 months so don’t have a lot of history with it. It’s at the Bentley dealership now so I’ll post what they find.
Dan

 

Hi Guys

Thanks for the replies, i have been reading the Pheaton self study hoping that something was going to jump out at me, unfortunately 90% of it went way over my head, am wondering why i bought something so bloody complicated as am a heating engineer.

As Dark Green suggested i have purchased the wiring diagram, it is coming tomorrow, hopefully i will understand that a bit better.

Fingers crossed Dan that your car gets sorted with out to much expense.

In Newcastle we are lucky as we have a independent Bentley/Rolls Royce company with an excellent reputation, will send the car to him if i cant sort it myself, however us guys are all the same and want to do everything ourselves lol lol.

Bob

 

Thanks Bob.
I’ll post as soon as I hear something. Seems like there are a fair amount of similar issues going on.

Dan

 

Bob,
The verdict was a faulty Phone module drawing down the battery while the car was off. Apparently the good news for me is with the aftermarket Pioneer AVH4500NEX Head unit installed, that module isn't required. Choice I was given was to spend a bunch on parts and labor to have it new module put in or pull two fuses and take the module off line. "Pull the fuses" , that was easy. The reason the instrument cluster died was part of the load shedding process and it needed to be reset. They reset the system and everything is working as it should. I'll have a few more details when I pick the car up this afternoon. Hope this helps.

Cheers,
Dan

 

So far so good. Car is back to normal. Fuses pulled to disconnect the phone module seems to have done the trick. Time will tell.

Dan

 

Hi Guys

Sorry for being such a long time in updating my post, i had no further information to post.

As it stands at the minute the car has been and still is at my local Bentley/Rolls Royce independant garage, top and bottom is that they have tried everything they can with the car, however the various control modules will not communicate with there Bentley software, apparently the car will not wake up the modules, it does however drive perfectly, but very worrying when the dashboard etc is dead.

The garage have contacted a specialist at Crewe, who has indicated the car can only be sorted by being put on there computer and connected to Bentley mainframe for more in depth diagnostics, getting very concerned now about what this is going to cost.

Will keep the thread updated when i have more info, in case anyone has the same issues.

BTW pleased your car is sorted Dan, thanks for keeping us updated on the repair

Bob

 

Sorry to hear that Bob,

If the fees are the same as a regular diagnostic scan at the dealer, it might not be so bad and will hopefully pinpoint the issue. Hopefully by 'mainframe' they mean a dealers diagnostic system that's connected to their system via internet, as opposed to having to get the car to their factory.

Has your independent been able to visibly or physically check or electrically test all the wiring looms? There's a few spots where these can chafe or get water ingress/corrosion damage, but I suspect they know that already.

Perhaps the independent can ask Crewe for the expected costs/process/locations before committing?

 

Thank you Bob. So far so good after taking the Phone module offline. Was hoping the same fix would work for you. Best of luck, hope a solution presents itself soon for you.

Dan

 

Hi Guys

Sorry for the delay in upgrading my thread, nothing worse than asking for help when things are not working, getting them fixed and not saying what was wrong/found, just in case someone else has the same problem.

Any way as previously stated the car went into the local Indy who did there best but could not resolve the issues.

The car then went to Bentley dealership, they could not fix it either, they took advise from Crewe who told them to connect it to there main frame computer and they fixed it remotely.

The car just went to sleep and they woke it up remotely, sounds strange to a mere mortal, but it done the trick, been working perfect for the last 3 weeks.

I asked them how it happened, they simply did not know………..the mystery’s of owning a Bentley!!!!

Thanks to everyone who replied to the thread.

Bob