Cheap flasher unit replacement
Posted: Tue Nov 19, 2019 10:25 pm
My original flasher unit finally died and I wasn't keen to pay the $150+ price of a new one, so I looked around and found the e28 unit has the same pinouts minus one, and can be had for $20 or so. The website for Werhle even lists the schematics and various models.
https://www.wehrle-electronics.com/en/t ... spx?LNG=en
It has the same 31, 49, 49a pinouts but is missing the "C" line. In our cars, this goes to the cluster indicator blinker, and the reason ours is so expensive is it has the smarts to blink just once when one of the bulbs is burnt out. I can live without that.
The e28s have a left and right dash indicators, so they don't need that line. How to make this one flash?
I used a bridge rectifier, taking input from the left and right indicators via the stalk plug making some Y cables because I don't like to cut the factory lines, removed the pins from the original flasher socket, and outputted the + side of the rectifier to the cluster indicator light.
I actually bought this particular bridge rectifier in a pinch on a road trip during summer when my AC compressor diode failed. Connected it up in the Frys parking lot and had much needed AC again.
Recently I also installed remote central locking installing the module in the drivers' door (there's power and it's easy to connect the master control and use the existing car wiring for all doors/trunk/gas cap), and used the 'impact sensor' line as output for the lock/unlock flashes. I found and clipped that line and hooked it into the - of the bridge rectifier. Be careful if you do this as there's multiple green/red wires, including power window supply lines. As they say measure twice cut once.
It now blinks on lock and unlock.
Per Mike W, the impact sensor is really a rollover sensor (thanks Mike), to unlock the doors in case of the car being upside down. I drive with my doors unlocked, besides its + signal isn't compatible with the standard negative triggered central locking systems.
Here's a picture and diagram to explain better. This might save some cash when your indicator flasher dies.
https://www.wehrle-electronics.com/en/t ... spx?LNG=en
It has the same 31, 49, 49a pinouts but is missing the "C" line. In our cars, this goes to the cluster indicator blinker, and the reason ours is so expensive is it has the smarts to blink just once when one of the bulbs is burnt out. I can live without that.
The e28s have a left and right dash indicators, so they don't need that line. How to make this one flash?
I used a bridge rectifier, taking input from the left and right indicators via the stalk plug making some Y cables because I don't like to cut the factory lines, removed the pins from the original flasher socket, and outputted the + side of the rectifier to the cluster indicator light.
I actually bought this particular bridge rectifier in a pinch on a road trip during summer when my AC compressor diode failed. Connected it up in the Frys parking lot and had much needed AC again.
Recently I also installed remote central locking installing the module in the drivers' door (there's power and it's easy to connect the master control and use the existing car wiring for all doors/trunk/gas cap), and used the 'impact sensor' line as output for the lock/unlock flashes. I found and clipped that line and hooked it into the - of the bridge rectifier. Be careful if you do this as there's multiple green/red wires, including power window supply lines. As they say measure twice cut once.
It now blinks on lock and unlock.
Per Mike W, the impact sensor is really a rollover sensor (thanks Mike), to unlock the doors in case of the car being upside down. I drive with my doors unlocked, besides its + signal isn't compatible with the standard negative triggered central locking systems.
Here's a picture and diagram to explain better. This might save some cash when your indicator flasher dies.