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Basic Installation Instructions for Time-Delay Relay


These instructions detail the basic installation of the Time-Delay Relay, which should cover most uses. If you have any questions, please feel free to contact us.

What's Included

  • Time-Delay Relay unit
  • 5  0.25" female spade terminals

What You Need

  • Wire for wire harness
  • Wire stripper
  • Crimping tool (or pliers)
  • Inline fuse(s)
  • Device to be switched
  • Optional: soldering iron

Warning: If you have a positive-switching TDR (TDR-P, TDR-PM, TDR-PS, etc.), disconnect power to the vehicle, or at least to the circuit you are working on, before wiring the relay. When wiring, make the ground connection first. During testing, do NOT remove the ground connection when the rest of the relay is under power, as this will destroy your relay.

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 system. The first step is to determine how the device you want to switch is 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.

Example 1: Single Device with TDR

Time-Delay Relay Connections
TDR Time-Delay Relay Connections

As you can see in this diagram, the Time-Delay Relay can be triggered by either a positive or negative signal. The TDR and the device should both be protected by a fuse, and the device's positive lead is connected to the fuse, while its negative lead is connected to the TDR's "L" terminal.

Example 2: Single Device with TDR-P

TDR-P Time-Delay Relay Connections
TDR-P Time-Delay Relay Connections

This diagram shows the positive-switching version, the TDR-P, instead. The "L" terminal is connected to the device's positive lead, while its negative lead is connected to ground.

Example 3: Dual Devices with TDR

Time-Delay Relay Connections
Time-Delay Relay Connections (2 Devices)

Here, there are two devices switched by the Time-Delay Relay (such as two HID ballasts). The main difference here is that the devices' positive terminals are connected to the battery, through three fuses. Each device has one 20A fuse, and the two then share a 30A fuse at the battery, which also protects the TDR. The secondary 20A fuses are important, because with them, if one device 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.

Example 4: Dual Devices with TDR-P

TDR-P Time-Delay Relay Connections
TDR-P Time-Delay Relay Connections (2 Devices)

This diagram shows two devices switched by the positive-switching Time-Delay Relay (TDR-P). As with the single-device setup, the devices' negative terminals are connected to ground, but the positive terminals are connected to the relay's "L" terminal through 20A fuses.

Now that you understand how the wiring will work, you just need to decide where to mount your Time-Delay Relay. The TDR case has two mounting ears with holes, and can be mounted on sheet metal using self-tapping screws.

Wiring Instructions

  1. Before modifying any wiring, disconnect the battery on your vehicle, so that there is no power applied to the circuits.

  2. After installing your Time-Delay Relay where you want it, locate the wire (or wires) you'll be using as a trigger or triggers, run these wires to your TDR, strip the wires and install spade terminals. Then connect them to the input terminals "1" and/or "2". The triggers are interchangeable; they are electrically isolated from each other, and either one will trigger the relay. If you are only using one trigger, you can leave the unused one unconnected.

  3. Find a suitable ground wire, or connect one to a clean spot on the chassis with a ring terminal and screw or bolt. Connect this to the TDR's "G" terminal using a spade terminal.

  4. Next, cut a length of wire long enough to go from the TDR to your battery (or whereever you prefer to get power from). Be sure to install an inline fuse, connect one end to your battery, and connect the other end to the TDR's "+12" terminal with a spade terminal. You may want to use red wire for this.

  5. Cut lengths of wire long enough to go from the Time-Delay Relay to each device that will be activated by the TDR.

  6. For the negative-switching versions (TDR, TDR-M, TDR-S, etc.), splice one wire to the wire you just connected to the TDR's "+12" terminal, and then connect the other ends to the positive terminal of whatever connector you need for the devices, installing an inline 20A fuse on each wire. You may want to use red wire for these two lengths of wire as well.
    Then cut lengths of wire the same length as the previous two, to go from the Time-Delay Relay to each device. Splice them together, and connect the joined end to the "L" terminal on the TDR with a spade terminal. Connect the other ends to the negative terminal of whatever connector you used for the devices. You may want to use black wire for this.

  7. For the positive-switching versions (TDR-P, TDR-PM, TDR-PS, etc.), connect one wire to the positive terminal of each device, splice them together, and connect the joined end to the "L" terminal on the TDR-P with a spade terminal. Then connect a separate wire to the negative terminal of each device, and connect this either to the same ground spot you used for the TDR, or to some other suitable ground connection on the vehicle.

  8. It's best to use wire of at least 16 gauge (AWG) size or larger from the battery to the devices, from the devices to the Time-Delay Relay, and from the TDR to ground. The wires connected to the "1" and "2" terminals can be smaller, as they conduct very little current.

  9. If you wish, you can solder the female terminals after crimping them. Note also that the blue sleeves on the included terminals are heat-shrinking. It is NOT recommended, however, to solder wires directly to the spade terminals on the TDR; this will warp the plastic casing of the unit, make it difficult to remove or rewire the device, and is unnecessary.
Time-Delay Relay Connections
Time-Delay Relay Connections

Testing and Adjustment

Now that your system is installed, you can turn it on and try it out, after setting the delays and trigger switch.

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 (this is the default position). 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.

Warning: Be careful when changing the switch position. Use a small tool, such as a miniature screwdriver, and push it carefully either left or right.

Now, before adjusting the delays, try powering on your vehicle. The delays are preset to zero. Your devices should come on immediately when either of your triggers 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 either a suitable ground (for TDR), or to battery power (for TDR-P). If the devices do not come on, check the fuses and then the wiring to make sure everything is wired correctly. If the devices do come on, check the wiring, but the TDR may be malfunctioning.

Time-Delay Relay Adjustments
Time-Delay Relay Adjustments

Turn off the device. By default, the Time-Delay Relay is shipped with the minimum turn-off time of 1/4 second. Your device should turn off about 1/4 second after turning off the trigger. 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. Note: There are no stops on the knobs. When you reach the adjustment limits, they will continue to turn with no effect.

If you wish to add a delay before the device turns on, adjust the knob marked "I" on the backside clockwise. Experiment with turning the device 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.