you will need to perform a test to see if your headlights are positive OR negative switched, and then utilize a Whelen UHF-2150A flasher wired accordingly. To check what type of headlights you have, follow these instructions:
With the vehicle off and the headlights off, test all of the leads going in to the headlight with a VOM or test light to ground. If you have power to any one or more of those leads while the vehicle is OFF, chances are you have a ground side switched system. This means that the bulb already has 12 volts to it, and the headlight switch system provides the grounds to the bulbs when activated.
For a ground switched system, with your test light connected to 12 volts, Have someone flick on the high beams while you probe, and if you get ground at one lead with the high beams switched on only, this is where you want to tie in (test the leads on both lights, imports usually have separate HB circuits). Make a note on each headlight which color is the high beam wire and wire your Whelen UHF-2150A according to the directions for whichever headlight switching you have.
With the vehicle off and the headlights OFF, if you have no power to any of the leads at the headlamps, chances are you have a positive side switched system and also tells you you already have ground to your bulbs, and the headlight switch system provides 12 volts positive to activate the bulbs..
For a positive switched system, with your test light connected to ground, Have someone flick on the high beams while you probe, and if you get 12 volts at one lead with the high beams switched on only, this is where you want to tie in (test the leads on both lights, imports usually have separate HB circuits). Make a note on each headlight which color is the high beam wire and wire your Whelen UHF-2150A according to the directions for whichever headlight switching you have.
Good luck.
