viper 5901 in a 2003 ford f 250

Here is a link to Bulldog Security for their wiring guide :  http://www.bulldogsecurity.com/bdnew/vehiclewiringdiagrams.asp   They include some nice pictures, too.

Here is a link to AudioVox for their wiring guide & tips :  http://techservices.audiovox.com/Login.aspx   Sign-up is free.

These are only guides.  Always verify all wires with a DMM. 

This site has the 5901 Install Guide in the Downloads section.  Just go to Downloads and search on "Viper 5901".  ( Your 5901 might be the newer version. )

Pay special attention to Bulldogs' Note #1 about the door locks and the Ford GEM module...

The relays' generic name is  30/40 Amp SPDT relay.  I believe they are available in better automotive part stores.  Also available online.

The diode is a 1N4001 but a 1N4004 will also work.  They are available at places like RadioShack.  Also available online.

This site has some good basic info on Diodes and Relays.  Look at the blue bar across and near the top of the screen.

In a typical install, you can locate the Viper 5901 in a position that will allow the supplied wires on the harnesses to reach their connection points.  There will also be many unused wires so they can be cut and added to any short wires if necessary.  

For the best reliability, it is recommended that all connections be soldered and insulated with quality tape or heat shrink tube. 

Have you purchased a bypass module yet? 

Plan on at least the entire weekend for your install. You will be spending time upside down verifing wires. As mentioned by kreg357, soldering is the best connection. I use a Weller 260/200w soldering gun. Heats up those heavy gauge wires real quick. I tried a 140/100 watt soldering gun, but it doesn't do very well on the heavy wires.  

My first install I tried scotch locks with miserable results.   I'm not a pro at this stuff, I have learned 95 percent of my stuff from the great people of this site.  I have done my cars, my kids cars and my brothers with great results thanks to the pro's here.  I guess I'm a Pro-DIYer.

Good Luck. Take your time. Double check all your wires. Use a good quality tape like Scotch Super 33+.