Kriss Motorcycle Products

Technical Support - B8 Brake and Trunk Light Flasher
Built on questions from users

Installation instructions must be followed exactly and all steps completed prior to applying power or the unit will be damaged. Connecting the unit backwards will damage the unit.

Problem

We are using this particular example to reveal what takes place more times than not.
We are providing this exchange so you can see the results of an incorrect installation. The customer bought a closeout model headlight modulator and returned it because he said it didn't work. We didn't find anything wrong and agreed to give him credit toward one of the newer models. He insisted that he knew what he was doing and did everything correctly.
Customer: I installed the replacement modulator tonight and it doesn't work either. It actually blows the motorcycle fuse when switched On. Prior to installing the unit I took great pains to insure it was connected properly and used a multimeter to confirm each wire of my circuit plug. I also tried it on my bench power supply and it makes the supply go into overload protection. I'm an electrical engineer so I understand electronics. Can I send this thing back for a refund? As much as I want it to work, I'm tired of messing with it.
Us: Sorry but that won't be possible. I can tell you without any doubt that you've connected the unit backwards. If it's blowing the fuse or putting a power supply in overload then you've blown the suppression diode in the circuit which prevents total destruction.
Note: We sent him a photo of the component in question and suggested he open the case and check the diode with an ohmmeter.
Customer: Thanks for the picture and explanation. I took the box apart and checked the diode. Not only was it shorted, but the top was blown off. I replaced the diode and hooked it up to my bench power supply. It worked fine. Before I hook it to the bike I'm going to go through the wiring again and double check things.

Be sure to check your battery, especially after all the testing on an installation.

Question: Unit overheated and box melted. Installer stated he connected to a ground location other than the frame or original ground circuit.
Answer: The ground connection did not provide proper current carrying capability which overheated the power components.

Question: Lights would not flash.
Answer: Attached output wires to original ground wires which had not been cut and separated from frame ground. After making a correction the lights worked properly. In this case the original ground wire was providing the ground to the bulbs rather than being controlled by the unit.

Question: Programming doesn't seem to work. I touched the wire and counted the flashes but unit didn't change program when the unit was turned back on.
Answer: After counting the programming flashes and disconnecting the program wire the power must be left on the unit for about five seconds before turning the power off and back on. This is because the programming is not completed for several seconds after the program wire is removed from +12 volts.

Question: How do I bench test the B8 Trunk Light Flasher Unit?
Answer: Connect either of the Orange/Black or Blue/Yellow wires (one at a time if using only one bulb for test) to a 12 volt bulb (even a test light is OK). This connection will be the ground side for the bulb. The other terminal of the bulb or test light should be connected to positive (+) 12 volts. Attach the green ground wire to battery negative first and then yellow wire to battery positive. The bulb, bulbs or test lights should illuminate. Touching the Green/Red brake sense wire to +12 volts should cause the bulbs to perform the selected flash sequence. You can even do the programming at this point in time. If the unit passes these tests the unit is functioning properly. If either one of the two outputs fails to flash the respective light then that side has been blown. Whether the bulb is on steady and won't flash or not on at all depends on the conditions at the time the IC was blown.

Always use a test light when checking circuits.