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109 relay symtoms- but not the 109 relay fix!

~TDIguy~

Veteran Member
Joined
May 4, 2017
Location
Romulus Ny
TDI
2005 Jetta Sedan
So i recently bought a 2004 jetta Bew that i had found on CL in Indiana. 343k miles but still pretty solid and with a brand new PD150 intake and VNT 17 that i thought would go good on my other BEW with the tuning and currently stock turbo.:D So i had a friend drive the car home, drove great and ran fine. He dropped it off in pa where i later picked it up and drove the rest of the way to my place in Ny. i drove it a little bit around here, to work a day or so and then parked it cause i dont plan to put it on the road but simply swap the parts and resell.
So the car sat for about a week or two in the lot without being moved, when i went out to start it beginning of this week it would crank but not fire. Had the typical 109 relay symptoms, no GP or CEL when you turn the key on. SO i ordered two 109s from IDparts. So yesterday i switched the relay so it would be ready when a guy wanted to come look at it, and :confused: it wouldnt start!! Same thing. Checked out all the fuses pertaining to starting, and after a 40 minute conversation with my VW tech friend we decided it has to be the ignition switch. Heres why we thought that. Terminal 87 on the 109 is hot with the key off, and terminal 85 is ground with the key off. Turn the key on, and the power and ground should switch between 85 and 87 like it does on my 05 BEW. but that is not happening. unfortunately the ignition switch did not change that. ANy of you guys have any helpful tips for me??? I have another guy that wants to look at it this afternoon im really hoping to get it going in time..... and oh yes i tried switching the 100 relay between my 05 and the 04 just in case, no difference.
 

~TDIguy~

Veteran Member
Joined
May 4, 2017
Location
Romulus Ny
TDI
2005 Jetta Sedan
Could not hear fuel pump running and neither did the GP start as they should have, we got 20 degrees or so currently... After a bunch of testing using a bew wiring diagram from a vw tech friend we figured out we had a bad ground to the 109 relay! Pins 87 and 85 are supposed to switch from power to ground and vice verse when you turn on the key and this wasnt happening. So a jumper wire supplying ground got me going for the moment, hopefully it doesnt give more trouble till i have time to check into it again...
 

algirdas

Veteran Member
Joined
Jan 23, 2009
Location
Cincinnati,OH (Dubwerx)
TDI
98 jetta AHU
Just had a similar problem with 03 ALH. Would crank but no start and no glow plug light.
Turned out to be a broken wire in the harness that triggers the 109 relay.
It was the blue/yellow wire from ECU connector to the blue plug in plenum passthru.
Fixed by running an overlay wire using Vw wire repair crimp kit.
 
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