How to make your own Daytime Running light Module
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Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
How to make your own Daytime Running light Module
Since many have asked me for this here it is. These are directions for a 81 Corvette. I'm sure this will work for most if not all C3's
Parts
2 Bosch 30 amp relays
2 10K resistors
2 10K uf capacitors
8 diodes
You will need to make two modules. One for Left turn signal and one for Right turn signal.
The factory turn signal wires are a pulsed 12 volts but you need a constant 12 volts to activate the relay. The cap and resistor give the relay 12 volt constant, once the turn signal is turn off the cap runs out of power and the relay releases and turns power back to the turn signal wire.
You need to dual diode each turn signal wire at the turn signal bulb. Do not do this in the harness going to the turn signals or your side marker lights will become daytime running lights also.
You will need to run a wire from the left & right turn signal to your relays.
Your ground should be ran to metal, do not ground to the ground in the factory wiring harness. This will cause your directional indicators on the dash to stay lit.
You will add a diode to the parking light wire and connect this to terminal 86 on the relay.
Terminal 87 on relay is not used. Make sure your relay harness has the diode going to 85 and 86 on the relay. This will stop any chattering from relay.
Fuse your 12 volt wire that will feed power to your relays 30
Disregard diagram about switch - if you want a on/off switch you can do it two ways. 1st put switch on your fused ignition wire or supply power to terminal 86 of relays.
You are basically doing a starter kill relay. The turn signal bulbs are getting 12 volts and the relay is breaking the circuit when the directionals or parking lights are used
Parts
2 Bosch 30 amp relays
2 10K resistors
2 10K uf capacitors
8 diodes
You will need to make two modules. One for Left turn signal and one for Right turn signal.
The factory turn signal wires are a pulsed 12 volts but you need a constant 12 volts to activate the relay. The cap and resistor give the relay 12 volt constant, once the turn signal is turn off the cap runs out of power and the relay releases and turns power back to the turn signal wire.
You need to dual diode each turn signal wire at the turn signal bulb. Do not do this in the harness going to the turn signals or your side marker lights will become daytime running lights also.
You will need to run a wire from the left & right turn signal to your relays.
Your ground should be ran to metal, do not ground to the ground in the factory wiring harness. This will cause your directional indicators on the dash to stay lit.
You will add a diode to the parking light wire and connect this to terminal 86 on the relay.
Terminal 87 on relay is not used. Make sure your relay harness has the diode going to 85 and 86 on the relay. This will stop any chattering from relay.
Fuse your 12 volt wire that will feed power to your relays 30
Disregard diagram about switch - if you want a on/off switch you can do it two ways. 1st put switch on your fused ignition wire or supply power to terminal 86 of relays.
You are basically doing a starter kill relay. The turn signal bulbs are getting 12 volts and the relay is breaking the circuit when the directionals or parking lights are used
Last edited by spedaleden; May 17, 2014 at 12:52 PM.
Thread Starter
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
Thread Starter
Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
