Volvo 2009 D13 Engine Won’t Start unless I wiggle this wire a bit

Hey guys so my problem right now is that my truck doesn’t start sometimes and when it doesn’t I open the hood and touch this “one” very specific wire coming from the firewall and bam It starts no problem. (Give a little wiggle)

Some details to note is when it doesn’t want to start there’s a certain solenoid click that I don’t hear
But when I touch that wire I here that specific solenoid clicking I can get you guys a video here shortly.

My guess is either corrosion or a short. I re-soldered the wire because i thought is was loose and it looked like someone worked on it before but it didn’t solve the problem.
Here’s is a picture of me pointing at it.
Any diagrams would help so I can test which wire it is thank you.

 

Here is a link to the video of what I mean by the solenoid clicks and sorry if you can’t hear it there’s an interstate where I’m at. Hopefully one of you techs have an idea of what it might be and which wire it is.

 

So after doing some research and looking up diagrams. My guess is this wire has some sort of break or corrosion.

It could either be the 12v supply wire that engages the relay to complete the circuit to the signal wire to the solenoid ground,
Or the signal wire itself from the relay to solenoid ground.

I will test the wire with a multimeter to confirm which wire it is, after I confirm that I will try to see if I can rewire/Hotwire it with brand new wire from the MCFC Connector to whatever terminal. and see if the problem persists. I will do it when the truck doesn’t want to start or disconnect the wire so I have 100% confirmation.

And I promise this won’t look like a hack job

This is the diagram I was looking at pretty straight forward hopefully

 

I’d say that’s been fixed before. Not uncommon for a previous repair to get corroded.
Older trucks had various relays or solenoids on firewall leading to the starter.

 

Yes you’re correct it has been repaired before I touched it. Hopefully Tracking down this old wire isn’t too hard so I can try to wire it with new wire hopefully that fixes the problem I’ll post on this thread probably on Saturday when I get the chance to look at it again.

 

You're super lucky you found it. Since that's part of a giant loom of wire I would REPLACE that wire once you figure out where it's going. not repair it.

I would not upset all the other wires in that loom just connect a new one on the outside, run it where it needs to go both ends, seal it up real good and secure it.

In other words, do pretty much what they did with the last fix, just do it better. I would definitely remove all that fresh tape first and see it there's something real obvious in there though.

 

Sounds good i will definitely do that. I wasn’t planning on messing with the bunches of wire in there I might cause another problem LOL

 

Anybody know what this side of the the relay connects too? Left where my multi meter diode is touching. It’s Relay R1: IGN active during cranking relay.

I’m gonna go ahead and check myself also thanks to anyone who helps out.

 

I just tested it with multimeter it goes to the ground on the starter.

 

So I disconnected the battery from the negative terminal to check again now none of the wires have any continuity.

just running more tests to figure where this wire leads to