I ordered and received a 2008 Chev 2500HD new from a local dealer. I ordered the vehicle with the "Snowplow Prep Package" which consists of a skid plate, and a heavy duty alternator. When it arrived, I also bought a 2008 Ultra mount 7 1/2' Western snowplow and installed on the truck. From the very start, I noticed that as you used the snowplow, the Battery voltmeter on the dash showed the battery getting discharged. With continued usage of the plow, eventually the 2-4WD switch no longer functioned, and eventually even the clock in the truck would get reset and go to 12:00... two ways to get out of this condition. 1. Drive highway speed for 10-15 minutes to allow battery to recharge or 2. Shut the truck off and restart and the voltmeter worked as advertised. I took the truck with the plow that first winter into the dealer, and after 15 minutes they said everything was fine on the truck. This past winter the problem continued, so again I took truck back to dealer, and again they stated all was well. I then took truck to independent mechanic, and we did some 'testing'. After using plow for awhile, battery voltage would go down to 13 volts, and voltmeter showed battery in discharge state. Went so far as to swap plows with another person who has a 2005 Chev 1/2 ton. Problem stayed with my truck. We also noticed that the Alternator never showed more than 120 amps of current draw, even though it is a 160 amp alternator. Also found that if alternator wire was disconnected while voltmeter showed battery to be discharged, that the battery voltage went up immediately to 13.9 volts while alternator was disconnected, and then go back to 13.0 volts as soon as wire connected back up. Took it back to the dealer with the plow with that information.. They then put their scan tool on, and found that with the snowplow connected, they only had to swivel plow from side to side twice before the ECM/BCM module would go into a 'fail mode' due to excessive current drain on the battery, and basically shut down the alternator to prevent it from being damaged. They also found that the ECM module always showed the signal to the alternator to be at 60% meaning the ECM module never told alternator to charge more than 60%. At this point, dealer also decided there was a problem and started to replace parts. they replaced ECM module, BCM Module, and alternator. None of these fixed the issue. They then contacted their GM Tech. Answer came back after GM techs talked to the engineers that truck 'was operating as designed' and that no changes would be made.. Nothing else the dealer could do, so I picked up truck and plow. I then opened a complaint with GM, who referred me to District Service Tech, who did more research, and got back to me with the same answer. Operating as designed, and nothing was wrong.. and complaint was closed. Here is my take on it.. 1. How can GM sell a truck (Heavy duty at that) WITH a Snowplow Prep package, and then tell me that the truck apparently can't handle the current drain that a snowplow puts on the vehicle. 2. If using a snowplow causes battery voltage to go down that bad to cause clock to reset and the 2-4WD mode switch to no longer function, then the alternator SHOULD be charging at 100%, or 160amps... and it does not. I am not an automotive engineer, but do understand computers. And to me, if the computer is shutting down the alternator operation and not allowing it to try to charge battery back up, at least up to the 160amp draw the alternator is capable of, then GM has a design problem in the computer operation in the truck. They SHOULD be able to change the electronic module programming to fix it. Unless GM comes out and says that a snowplow is not supported on the 2008 Silverado 2500HD, and that you can't run a snowplow on their "Heavy Duty" truck, AND give me my money back on it or at least make it right, , or fix the computer programming in the ECM module so that it does NOT tell the alternator to 'shutdown' just because a snowplow is attached.