Can I use a 12v radio in my truck or is the truck system 24v? Im going to try and put an in-dash nav unit in my 99 international. The navigation unit im trying to hook up has wires that goes to the reverse lead, parking brake and a speed pulse cable. So I would like to know if I can access these wires from my truck? Has anyone out there ever hooked up an in-dash navigation unit? Do I even need to hook up all those wires? Thanks

Modern trucks are usually 12v neg ground, just like a car.

As far as hooking up an indash unit, if this is a company truck I suggest not splicing into any wires. The company may view this as tampering/altering company equipment and fire you.

From about the mid 70's to the present, all class 8 trucks have used a 12 volt negative ground system.

If you're not confident about hooking things up properly, have it done professionally.

The truck is mine. I used to installed car stereos years ago for a living and still do it for some friends from time to time, so I feel confident about trying it. But where can I go if I find out I cant do it? I just wanted to see if anyone has put in a aftermarket stereo system in there truck. Ive never dealt with truck stereos, but it seems like its not much different than car audio. Thanks for the quick replies!!

If you use to do install in cars then you shouldnt have any problems. I threw an aftermarket in my Freightliner in about 10 minutes after i went and got an adaptor from best buy so that i wouldnt have to do a bunch of splicing to the trucks wiring.