These instructions detail the installation of the Time-Delay Relay on a H4/9007 HID Headlight System, as this is the most popular use of this relay. Installing this relay on other systems, or using it to control other devices, is very similar, but if you have any questions, please feel free to contact me.
What You Need
Before you start hacking on your vehicle's wiring, you should probably plan out exactly how you want to install your Time-Delay Relay, and the rest of your bixenon system. The first step is to determine how your vehicle's headlights are already wired. If you can get a diagram from your vehicle's service manual, or perhaps a Haynes or Chilton book, that would be best, but if not, you can still figure it out pretty easily.
Below is a diagram of an example positive-switched system in stock form, from a 1994 Honda Civic.
As you can see in this diagram, the combination switch's dimmer function only allows current to flow to either the high-beams or the low-beams, but never both (unless the passing switch is held on). Wires from this switch go to the fuse box, and then four separate wires go to each headlight bulb (two to each side). This delivers power to the bulbs, which are then connected to ground, somewhere on the car's frame.
Now here is a diagram of this same system, but modified with bixenon HIDs, and using the Time-Delay Relay. This diagram shows a single TDR being used for both HID ballasts, but if you prefer to use two TDRs for maximum redundancy, it should be simple to see how to hook them up.
|Modified Headlights with Single TDR|
Here, the halogen headlight bulbs are gone, and replaced by HID bulbs and ballasts. I also illustrated this system with my bixenon solenoid controllers, but if you're not using Bosch 3-wire projectors, then this doesn't apply to you. As you can see here, the four headlight fuses in the fuse box no longer power the system. Instead, the high-beam wires are connected to the bixenon solenoids (or controllers), and the Time-Delay Relay is connected to one set of high and low beam wires.
The HID ballasts' positive terminals are connected to the battery, through three fuses. Each ballast has one 20A fuse, and the two then share a 30A fuse at the battery, which also protects the Time-Delay Relay. The secondary 20A fuses are important, because with them, if one ballast fails and blows a fuse, it's most likely to blow the 20A fuse nearest it, leaving the other ballast powered on so that you still have one working headlight. The 30A fuse protects the whole system, including the remote possibility of a defective TDR.
|Modified Headlights with Dual TDRs|
This diagram shows the same system, but with dual TDR relays instead, one for each headlight. This provides the maximum in redundancy and reliability. Each ballast has its own TDR, and each TDR, along with its associated ballast, is protected by a 20A inline fuse. This system requires two TDRs instead of one, but only needs two inline fuses instead of three.
The Time-Delay Relay is designed for low-side switching, so the ground/negative terminals of the HID ballasts are connected to the "ballast" terminal of the TDR, which then connects and disconnects them to and from ground. Finally, the TDR's ground terminal is connected to a suitable ground, perhaps one which one of the headlights used.
Now that you understand how the wiring will work, you just need to decide where to mount your Time-Delay Relay, along with your other HID components if they aren't already installed. You should probably install it someplace where it won't be hard to route one set of low and high-beam wires to it. The TDR case has two mounting ears with holes, and can be mounted on sheet metal using self-tapping screws.
|Time-Delay Relay Connections|
Testing and Adjustment
Now that your system is installed, you can turn it on and try it out.
First, you should determine if your triggers are positive or negative, and set the polarity switch on the TDR accordingly. If your trigger is positive (goes to +12V when "on"), then set the switch off. If your trigger is negative, then set it "on". If you don't know, you can try both settings, as the TDR simply won't turn on if the setting is wrong.
Your lights should come on immediately when either your low or high beams are on. If one or both of them do not come on, try disconnecting the wire from the "L" terminal of the Time-Delay Relay, and connecting this directly to a suitable ground. If the ballasts do not come on, check the fuses and then the wiring to make sure everything is wired correctly. If the ballasts do come on, check the wiring, but the TDR may be malfunctioning.
If everything looks fine, try switching between high and low beams. The HID lights should remain on, without any flickering.
|Time-Delay Relay Adjustments|
Turn off the lights. By default, the Time-Delay Relay is shipped with the minimum turn-off time of 1/4 second. Your lights should turn off about 1/4 second after turning off the headlight switch. If you wish to increase this time, remove the TDR from its mounting location, while keeping the electrical connections intact, and use a very small flat-blade screwdriver to turn the adjustment knob marked "O" on the backside clockwise. These knobs have 20 full turns of adjustment, so it may take many turns to reach the desired delay time.
If you wish to add a delay before the lights turn on, adjust the knob marked "I" on the backside clockwise. Experiment with turning the lights on and off, and adjust these knobs, until you reach the desired turn-on and turn-off delays, then replace the TDR in its normal mounting location.