filter out pulse width voltage?

I want to wire in some spotlights on a 2008 Dodge Ram.

The problem is it has daytime running lights which cannot be unplugged, can only be unprogrammed by the dealer.

The DRLs put a pulse width voltage to the high beam so I can't just use the high beam to flip my relay, I didn't really want to cut a switch into my brand new dash.

Is there a way to have the relay only switch with the high beam input and not be affected by the DRL voltage ?

Have you tried to install a relay on the high beam?  Depending on the duty cycle of the PWM signal it may not be enough to energize a relay when only the DRL are on. 

Another alternative would be to use a low pass filter like this: http://www.ontrak.net/pwm.htm

You would then have to add a comparator circuit to look for a voltage significantly higher the the voltage produced by the DRL.  The comparator circuit would consist of a two input comparator chip (one input to the output of the low pass filter the other to your reference voltage created by a voltage divider or pot.  The output of the comparator chip would have to drive a transistor that can drive a relay.

I haven't tried it yet but I had the same thing on an old Dodge Dakota and it the relay would buzz for a while then click on, I don't want to risk any problems in a new truck with more complex electronics (doesn't have any relays, or done by chips I think).

I think I will put a switch in the cabin to turn off the high beam supply to the relay when the lights aren't on.

I think I get what you mean, instead of grounding the relay coil as you would normally do I run that relay pin to the low beam supply and that way the relay will not energise with the sidelights alone.

Just need the clarifiaction as I have only wired relays in the normal grounded fashion before.

Thanks