I bought an after market HD light system for my 02 ram.. it's a plug and play system so it comes with all the factory plugs and all...The problem that I'm having is when i disconnect the factory lights and hook in the HD lights up the computer isn't seeing the lights and it throws a code so the lights don't wrk.. Is there a way to dummy out the computer so it thinks the factory lights are there???

 

You need a resistor b/c a HID bulb is only 35w and stock are 55w (I believe) There are many threads on this too.. Make sure you do a search

 

this is the single most discussed topic on this forum....just look around a lil bit

 

Agreed!!

Our trucks PCM and FCM read a resistance measurement through the headlight and tail light bulb filaments. When a filament blows the resistance drops and this lets the PCM/FCM know a bulb is out and two things happen here.

1) the modules reduce voltage and
2) the Lamp Out on the dash comes on to notify the driver

So because HIDs are gas filled and not a filament type bulb, when you plug them in the PCM/FCM module does not see "bulbs" and those two things stated above happen.

But because the voltage has been reduced, the HID kits will normally strobe or flicker.

The OEM filament type bulbs are 55w/65w bulbs. One the headlight harness plugs there are three wires. There is the low beam (12v), the high beam (12v) and the common (-).

So my taking 50 watt load resistors and adding them onto the HID harnesses, we can used them to replicate the resistance needed to trick the PCM/FCM into thinking there are bulbs there and that will reciprocate the two issues stated above. In other words, full voltage will be supplied and no Lamp Out light on the dash.

Specifically, the resistors get wired as such. We know there are two ends to each resistor and there are three wires on each headlight. Take one load resistor and splice it to the low beam (12v) wire and the other end to the common (-) wire. The other resistor goes with one end spliced to the high beam (12v) wire and the other to the same common (-) wire.

Those resistors can be found on ebay like these here.

http://cgi.ebay.com/ebaymotors/50W-6...#ht_3505wt_939

http://cgi.ebay.com/ebaymotors/50W-6...#ht_5379wt_919

or ebay item number 140418421659 and 230534203924 if those links dont work

 

Weedahoe.....Thank you for the info...I haven't been on this site in a long time so I haven't read any of the topics.. I appreciate the info....Do these resistors have to be installed on both head lights or just one side? The company i bought the HD lights from told me to resistor out only one side and i did that and it didn't work. So im assuming that it has to be done on both side to fake the computer out?