Please remember that I am not a professional installer, this is how I did this in my truck and it works for me, there might be a better way, Do this at your own risk!!
1 DEI 545T module
1 Extra 30-40 Amp 5 pin relay (3 total)
wire, wire crimps, solder, etc.
The DEI module comes with 2 relays, one is for Headlights the other for Parking Lights. On my truck I tried to eliminate one, while I was able to get the module to function properly, the headlight system acted as if there was an open in the circuit. Constant dinging like the headlights were left on, even though they were not and no key in ignition.
Red- 12 volt + constant (required)
Orange- ground when armed, Connect to Ground when Armed output of the security system (optional)
Black- Chassis Ground, use a good solid ground. At drivers side kick panel there is a factory grd. location. (required)
Blue/white stripe- Aux. RF channel input of alarm system. (optional)
Yellow- 12 volt + switched ignition, I used a pink/yellow stripe at the steering column. (required)
Green- Wiper switch input - negative (optional)
Violet- Wiper switch input Positive (optional)
Relays 1 & 2 that came with the DEI module
Brown- pin 87, parking light relay input. Connect this to a Constant 12 volt + Positive source (required)
Violet- pin 87, Headlight relay input. Connect this to a Constant 12 volt + Positive source (required)
Blue- pin 30, parking light relay output, Not connected to anything!!! (required)
Green- pin 30, headlight relay output, Connect to pin 85 on third (extra) relay. (required)
Now pull out the dash panel that holds the Headlight switch, Mine had six wires but eight pins. On the switch you will see numbers for each wire. You might need to unplug it first to see the numbers. Top right corner should be pin eight (8). On my '05 this wire was white / green stripe. Cut this wire in two leaving enough to splice onto both halves. Take two wires around 12" long and connect to the wire(s) you just cut, noting which is which, (wire leading towards truck harness- and wire leading towards plug that connects to switch.
Relay 3 or extra relay
Pin 85- connected to pin 30 Green wire for Headlight relay output (required)
Pin 86- connect to Ground (required)
Pin 87- Not connected to anything (required)
Pin 87A- Switch side wire, the 12" or so wire (required)
Pin 30- Truck side wire, the 12" or so wire (required)
I placed the Photo Cell on top of the dash, kinda pinched between the windshield & dash, with wire under the speaker cover. It has a sticky back but with the hot Florida sun it won't stick. You can place it anywhere you feel it will get direct sunlight.
Hope this is as easy for you guys as it should be!!! As you can see I did not connect anything other than the Auto Headlights/Parking lights. For wipers to turn on your headlights, you need to splice one more wire, after you determine the polarity of the wipers. And for the alarm interface you splice two more wires, very easy... On my module the DRLs were not enabled, if you did want them inside the sliding cover there is a wire. Make sure this wire is not cut.
Please ask any questions, I will do my best to help!!! Also if anyone has a better way please post it up!!!