n1das
TDIClub Enthusiast, Veteran Member
- Joined
- Jun 11, 2002
- Location
- Nashua, NH, USA
- TDI
- 2014 BMW 535xd ///M-Sport, 2012 BMW X5 Xdrive35d, former 3x TDI owner
A coworker of mine recently experienced the classic Relay 109 failure in his 2000 Jetta TDI. He still had the original Relay 109 and replaced it with the updated Relay 109 and his car is running fine again. TDIclub played a big part in educating him about the classic Relay 109 failure in older VWs.
Meanwhile he decided to open up the old relay and analyze the failure. The relay contacts appeared OK under a microscope. The contacts actually were not burned or pitted at all and no metal migration from one contact to the other...still good. While looking under the microscope we also took a look at the solder connections on the PCB and found a few that looked suspect. The pics below say it all....
Relay 109....
A few solder joints on the PCB looked suspicious.....
The large solder joint to pin "30" was cracked and broken, making intermittent contact:
Here's another view of the same (cracked and broken) solder connection:
We also found one of the smaller solder connections to be cracked and broken. This connection feeds one side of the
relay coil. Intermittent contact here would cause the relay to drop out and kill power to the car.
After re-soldering all connections on the PCB, he now has a spare working Relay 109.
Meanwhile he decided to open up the old relay and analyze the failure. The relay contacts appeared OK under a microscope. The contacts actually were not burned or pitted at all and no metal migration from one contact to the other...still good. While looking under the microscope we also took a look at the solder connections on the PCB and found a few that looked suspect. The pics below say it all....
Relay 109....
A few solder joints on the PCB looked suspicious.....
The large solder joint to pin "30" was cracked and broken, making intermittent contact:
Here's another view of the same (cracked and broken) solder connection:
We also found one of the smaller solder connections to be cracked and broken. This connection feeds one side of the
relay coil. Intermittent contact here would cause the relay to drop out and kill power to the car.
After re-soldering all connections on the PCB, he now has a spare working Relay 109.
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