Diodes and Diode Relay

The F650GS and G650GS use switches in conjunction with diodes to provide separation of circuits in the wiring harness. These are either housed individually or in a relay housing named the DiodeI relay.

The electrical diagrams for both the single spark and dual spark models have errors and omissions which make fault finding of diode faults more difficult.

The information below and in the starter circuit repair page combines information from online fiche and the single and dual spark wiring diagrams to make fault finding and understanding the diodes easier.

There are minor differences in wire colors and BMS connection so there are 3 diagrams.

See Starter Circuit page for information on load relief relay operation.


Lock Out Switches

The Clutch, Neutral and Side Stand switches work in conjunction with the diodes.

Clutch and Neutral Switches

The clutch and neutral switches are simple switches which cant be repaired. Check with a multimeter, replace if faulty.

Side Stand Switch

The side stand switch can be problematic when the retaining circlip is dislodged or it is affected by heat from the exhaust.

See Mods/SideStand and Repairs/Gearbox pages for more info.


Diode Relay

The diode relay is in the electrical box and houses the following diodes

2 diodes for isolation of front and rear brake lamp circuits
2 of the 3 diodes for the starter circuit lockouts.

Diode Relay and Starter Circuit Diagram (2000 to 2004)
Diode Relay and Starter Circuit Diagram (2005 to 2012)
Diode Relay and Starter Circuit Diagram (2013 to 2014)

Diode Relay Base

The relay base connector numbering for the diode relay is from the online parts fiche.

The electrical diagrams are inconsistent on diode numbering.

Brake lamp diodes are between pins 3,4,5

Starter circuit diodes are between pins 1-2 and 6-7

Brake Lamp Diodes

Some 00-01 and 05-07 wiring harnesses have a 4 pin diode relay.

The relay is no longer available, use the 7 pin relay.

See the pdf for details 00-07 Diode Relay

Individual Diodes

There are up to 4 diodes in individual plastic housings in the electrical box

3 diodes for the hazard warning lamp system (Dual Spark)
1 diode for the starter circuit lockout. (Single and Dual Spark)

BMW Diode Specifications Alternative Diode Specifications
Hazard Flasher Diodes (Dual Spark)

The hazard lamp diodes are under the relays in the electrical box
A failure in these diodes can prevent turning off the ignition.

There is a good write up at F650.com on replacing the diodes.
Hazard Flasher Circuit Repair Hazard Flasher Circuit Repair.pdf

An indicator cct diagram is available here Indicator Cct Diagram

 

See Modifications/LED Indicators page for Flasher Relay information.


Diode Repair Images

Credits - RkyMtnMan from f650.com for the images and excellent write up on the repairs.