[wingman26]

We have had a 2016 3.6ltr dropped in to us and we have very limited info on the car electrical side. the fault is when pressing the start button it does not turn ignition lights on and have no wipers or windows or heater working. We found rear fuse box to be full of water had a new one sent over which fitted today but still have all above same faults. it locks and unlocks all lights work just no Ignition has any one come across this or do you know if it has a Ignition relay somewhere?? customers organial fault was it was getting harder to get the Ignition to come on when pressing the button.. Do you know if rear fuse box in boot has to be programed to the car, any help or advice would be greatly appreciated

[arpad_m]

The starter relay and fuse are in the front fuse box, K10 and F13, respectively.

When these cars suffer water intrusion in the trunk, all bets are off, the entire rear fuse compartment needs to be inspected for rusting and shorts (the Bose amplifier, if equipped, may be a goner as well). That said, AFAIK no starter electricals are wired to that box, so you should at least hear the starter relay in the front activate when you push the start button.

If you get cranking action but no start after inspecting/replacing the fuse and relay up front, the fuel system control module fuse (F35) is in the rear fuse box, that may need attention, too.

[wingman26]

Thanks for the info sent over, I have replaced the rear fuse box today along with new battery, nothing happens at all when starter button is pressed, sometimes the millage will flash up along with park brake light. all earths are good front and rear and all supply feeds are good, I will remove the rear trim on the drivers side in the boot and check in there

[wingman26]

Update on things, I bridged out starter relay today and it cranks over fine, removed stoplight switch to check operation all fine, but still can not get ignition to switch on, any more advice would be appreciated

[arpad_m]

Are you saying the starter cranks, but there is no spark and/or fuel? Can you hear the fuel pump prime when you open the driver door (after leaving the car turned off for a few hours)?

[wingman26]

Thanks for reply..Yes it cranks over fine, no spark or fuel as can not get any ignition supply feeds to ECU

[arpad_m]

That sucks... I'm sorry, but I have no other ideas than to grab the service manual and start going through the electrical checklist, starting with the DTCs if any. Harnesses, including the main body wiring harness under the trunk area, may have been compromised.

[wingman26]

Yea I know, I can't pull any codes out because can't get the ignition to switch on, all trunk wiring is good no damage at all, I have a feeling that there is an Ignition relay somewhere on the car but don't want to rip the car apart to find it, with being in the UK there is very little information we can get on it

[arpad_m]

Well, if you want to "play" whack-a-mole, here are the other relevant manual pages with fuse and relay info. Good luck, hope you'll figure it out eventually

[wingman26]

Thanks for the info, i will let you know how things go

[wingman26]

Had a chat with customer last night he also tells me it has been hard to switch OFF the car when pressing the button.. Do you have a wiring diagram for the push button at all?

[arpad_m]

I have the 2018 service manual for my car, see a few related electrical diagrams below.

However, there are hundreds of pages about the starting and charging system alone, and the entire service manual is about 10k pages, with information and cross references spread throughout sections. There is no way anyone can post all the pertinent info here.

What I'd suggest is that you buy a 3-day subscription from AC Delco at https://www.acdelcotds.com/subscriptions, which gives you three days to download everything you need.

[ctrlz]

wingman, search here for threads by lynyrd. He had a thorough soaking of the rear fuse box and multiple problems which he fixed.

[SpeZ]

There you go.
https://drive.google.com/file/d/12V6...ew?usp=sharing