Kriss Motorcycle Products

Technical Support - Dual H4 bulb Headlight Modulator
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: After installation the unit would not modulate. The bike was still in the garage under florescent lighting.
Answer: The IR detector is not triggered by florescent light. It requires either sufficient sunlight or an incandescent bulb.

Question: 2004 edition. After installation the unit would not modulate. A flashlight was used to trigger the IR detector.
Answer: The light was not left on the detector long enough. There is a one second delay in the new 2004 programming.

Question: After installation the unit would not modulate correctly or stop modulating. The flash rate was very slow, about 1.5 seconds on and 1.5 seconds off. The unit was returned for inspection and found to function properly.
Answer: The customer incorrectly attached the programming wire to a +12 volt source. The unit was in constant programming mode.

Question: How do I bench test the modulator Unit?
Answer: Connect either of the Blue output wire (with attached 3 position plug) to a 12 volt test bulb (even a test light is OK). Attach the Green ground wire to battery negative first and then the Blue input (spaded) lead to the positive post. The input wires are always in the larger bundle of wires. The test light should illuminate. Shine a flashlight on the light detector to confirm the light modulates. Remember that there is usually a one second delay before modulating and a four second delay after removing the light from the detector lens. The White/Black wire is the low beam and doesn't need to be connected.

Always use a test light when checking circuits.