TDR Application 1: H4 or 9003 Headlight HID Conversion

Keep HID ballasts on in low-beam and high-beam modes

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On any halogen-equipped car that is being converted to HID, it's considered best practice to use a relay to connect the HID ballasts to the car's battery (through a fuse of course), so that the factory fuses for the regular headlights aren't overloaded and blown because of the HID ballasts' high start-up power draw. On a car with four headlights (two per side), this is pretty easy: you can just use a standard automotive relay, available cheaply at any auto parts store, and connect it so that the low-beams are used to turn on the relay. This way, whenever you turn on your headlights, the HID ballasts will turn on, and power your HID low beams. When you switch your high beams on, your low beams (HID) will of course stay on, and your halogen high beams will also come on, or if you have bixenon projectors, your bixenon solenoids will activate, giving you HID high beams. This is because, in most 4-headlight cars, the low beams stay on when the high beams come on.

However, in 2-headlight cars (with one headlight on each side), things work differently: there is only one bulb per side, with two filaments inside, one each for low and high beams. Common numbers for these bulbs are H4, 9003, 9004, and 9007 . On cars with these lights, when the high beams are turned on, the low beam filaments are turned off. This means that connecting a relay to this system to power HID ballasts isn't so simple: there's no single wire that's powered when your headlights are on, which you can use as a trigger for your HID relay. If you connect your relay to your low beams, as on 4-headlight cars, your HIDs will turn off when you turn on your high beams! And since cars like this are usually retrofitted with bixenon projectors, and have no separate halogen high beams, this means they have no headlights at all in high-beam mode!

One simple solution to this, commonly found on the internet, is to connect two diodes to the relay's control pin, and connect each of these relays to the low and high beam wires. This works, but it's a bit messy, requires soldering, and just doesn't look very good. In addition, there's a small delay when switching between high and low beams, which will cause the relay to switch off very briefly, and this probably isn't very good for your ballasts.

The WolstenTech Time-Delay Relay offers you an easier, cleaner solution to this problem, with the following features designed to make your HID retrofit on an H4 or 9003-equipped car easier:

• Two independent, isolated input connections, for connecting to your low and high beam wires.
• A minimum turn-off delay of 1/4 second, so that ballasts never lose power during low/high switching.
• An adjustable turn-off delay of up to 60 seconds, so that, if desired, headlights will stay on for some time after turning off headlight switch.
• An adjustable turn-on delay of up to 60 seconds, so that, if desired, headlights will not turn on for some time after activating switch.
• Works with both positive and negative-switched headlight systems, so you don't have to worry about finding out which kind your vehicle is before ordering.

Example 1: Single TDR

Example 2: Dual TDRs

Example 3: Single TDR-P

Example 4: Dual TDR-Ps