98 V70 NA base - Fuel flap wiring help needed Topic is solved

Post by **scot850** » 26 Mar 2022, 19:31

Ah, the gift that keeps giving! The car is back again for 3 things and that has multiplied as usual.

The issue I am working on I need electricery guidance. Owner thought the issue was cold weather and the flap release solenoid not working. I lubed it and when I had the car the flap worked 100% every time. Needless to say the issue came back. Did seem to be tied to the cold weather initially but now it seems permanently not working.

I planned to try a belt and brace approach. First, check the motor when out the car. It worked perfectly as I expected it to. Does not work from the button on the driver's door at all.

Fitted a 2nd hand flap solenoid motor which I have modified with an 850 manual pull wire should it fail again so it can be released.
I fitted this and made a simple bracket to route it to the small removable flap in-front of the rear lights. Left this off for now so it is accessible.

Next, went to the driver's door. Found the check strap is totally disintegrated. This has allowed the door to over open and was crushing the door wiring harness against the remaining part of the check strap. So I'm thinking the wire may be broken in there. I've taken the door panel off and checked the flap switch and again operated 100% when powered. Still nothing at the flap when connected.

Tomorrow I plan to remove the multi-pin wiring connector on the 'A' pillar that feeds the driver's door and then buzz it out. to see if the wire or wires are broken. If any are broken I will have to try to deal with that which on this harness is a royal PITA due to lack of room. The wires love to break right at the connector giving little or no way to repair them. Just love that!

What I need is a pin out for the connector/harness at the door. Does anyone have that they can post for me? It will save me a lot of time trying to buzz all the wires out to figure out which is which pin.

Thanks,

Neil.

Post by **abscate** » 27 Mar 2022, 05:31

Say hello to my little friend , the 2/76 lockcontroller

Warning …this is the 1999 diagram. I’m 99 44/100% sure it applies to the 1998, too

This is a digitally controlled release through the white module under the dash, so the BFC ( big fat connector) 24/50 is of limited utility Electrically troubleshooting.

I would pull the B connector on 2/76 and put 12 volts on B12 pin to see if that pops the fuel door first

The door fuel switch 3/109 is giving logic signals to 2/76 to prompt release. That’s two cups of coffee away from me figuring that out

Post by **scot850** » 27 Mar 2022, 09:17

I'll try to figure out the wiring diagram you have posted (you know how I love wiring issues!!) and thanks for that.

I think what you are saying is basically my plan. I will disconnect the harness at the multiplug on the door. If I can figure out the pins in the connector I will short the 2 pins for the fuel flap and see if it operates the solenoid motor. If that is good, then I will buzz out the wires on the door section and see if the harness is broken in the impossible to get to covered section between the door and the multiplug. If it is then I will have the fun of trying to fix the harness in situ.

I also remembered after posting this I had posted about the repair on my door harness on the 'R' which when I read reminded me I had a cut section of the harness wit the multiplug opened up so should help to narrow the pins down.

Thanks!

Neil.

Post by **BEJinFbk** » 27 Mar 2022, 10:16

Have you considered pulling the door off
to provide better work access to the connecter?

Post by **scot850** » 27 Mar 2022, 10:26

Funny coincidence, I have just had that discussion with my son. If I had a lot more time I might do that. First I will identify the cause in case it is not the wiring in the door after all and is maybe in the controller unit abscate mentioned above.

Thanks,

Neil.

Post by **scot850** » 27 Mar 2022, 10:30

This was the post I did on my 2000 'R' when the passenger door mirror adjustment stopped working.

https://www.matthewsvolvosite.com/forum ... ss#p454141

Neil.

Post by **abscate** » 27 Mar 2022, 11:25

I’m guessing that the fuel button grounds, simaltaneously ,A16 and A18 to trigger the opening of the lid

Post by **scot850** » 27 Mar 2022, 13:16

Yes that is how it appears. Tracing the wiring is a real pain until I printed off your wiring diagram above. The Haynes one is misleading and had me chasing the wrong wires. From your diagram above, I discovered the wires from the door switch both run up into the master switch and not directly to the multiplug.

So the Yellow/white wire I was chasing was the wrong wire (it is actually the trunk wire switch beside the fuel flap) and what I should have been chasing was a Black/ground wire which goes to the master door switch and then runs and joins 2 others hidden inside the wire boot. Bottom line was these were all good and the other 2 items worked so would tend to say the ground wire was good.

The blue/gray wire from the switch goes into the master switch and comes back out as a grey/red wire. All seemed to be good there too (I had disconnected the multiplug for buzzing out the wires).

Tried swapping the master switch and still nothing. Then the 'D'oh' moment!! I was buzzing out the wrong wire again! When I buzzed out pins #6 and #16 and flicked the switch for the fuel flap it worked fine. Now even more baffled, reconnected the master switch and the fuel flap now works again.

I tried opening and closing the door multiple times as I am still suspicious the wire may be bad in the harness. Still, so far, so good.

Did I ever say I hate wiring???? I am still not convinced this is permanently but I hate chasing electrical things that are intermittent.

All I can hope now is that it was just a bad connection in the multiplug and so sleep better!!

Neil.

Post by **scot850** » 27 Mar 2022, 20:01

Thanks again to moral and advice from a poorly abscate! Thought the hard part was the wiring. I have sent the owner away with a modified manual release like an 850 for her car so if the button decides to play silly beggers again at least she can open the flap.

Like abscate says, it is likely a pulled or cracked wire in the door to 'A' pillar section inside the rubber boot. As suggested the easiest way to probably tackle repairs is to remove the complete door to give better access to work on the wiring repairs. That will have to wait for another day. I had hoped I may have accidentally fixed the issue by a poor connection somewhere. I did note that when I re-tightened the multiplug outer ring to the 'A' pillar that it did easily tighten about another 1/4 of a turn to how it was originally. Time will tell! Car was sent away with a white-line warranty!

Neil.