is this possible, alarm burn pcm?

i would first find out which wire was the wrong one.

Next find out which fuse is blowing.

Next spend 11.95 at   http://www.eautorepair.net/Marketing/Default.asp

You should be able to determine from that if is your fault or not.

The only way it could be your fault is if you tagged into the wrong wire

p.s, i would avoid playing russian roulette with another pcm.

The voltage surge is a bag of crap how can 12 volts produce more that 12 volts?

A failing power supply, using a 12v source, can easily produce more than 12v on it's outputs.

If the customer believes his mechanic over the shop this is pretty much the ONLY way to prove to the customer that the alarm didn't cause the failure.  It all comes down to how confident you are that you didn't cause the problem.  If your alarm did cause the problem then this will pretty much verify you were at fault.  It also depends on who is going to be paying the repair - I'm assuming it would be covered under insurance, but I could be totally wrong there.  In an insurance claim a few hundred extra dollars won't be a huge deal - if the cost is coming out of pocket AND you think you might be at fault then the "try a new PCM" idea probably is not a good one.

It's just important to let him drive the car for a while before hooking the alarm back up to make sure there isn't something else in the car causing the problem.

If the problem was caused by a faulty alarm system (which I still don't believe) who would be at fault?  I know the alarm manufacturers don't warranty anything past their alarm, even if the alarm did damage something else.  If a shop installed a defective alarm properly would they still be liable for the damaged caused by the faulty alarm?  I've never ran in to such a circumstance.

Another thing that would be interesting to know is what exactly "burnt" on the PCM.  Request that his mechanic draw out the damaged circuit - starting from your alarm connection, to the PCM, and then, in writing, have him report what circuit is damaged inside the PCM.  If his response is "the PCM is burnt thats all I know" then how can he possibly relate this to the alarm install?

This whole situation reminds me of a thread on here about a year ago about a guy who had a remote start installed on his van out in NY (I believe) and the van made it about 1/2 mile down the road before the tranmission failed.  He, and his shop, blamed the remote start, but ultimately in the end the courts decided it was in fact a coincidence.  I'll see if I can find that thread, it may be a good read.

and what part of a remote start or alarm has a power supply?

Every car alarm I've ever opened up operated on 5vdc, so there is a power supply in every one I've ever seen.  Usually just a voltage regulator and a few caps

I doubt it would have the capacity to damage a cars PCM though, like I said the cars ECU should be built to handle pretty much anything that could go wrong in a cars electrical system.

Thank you!  Being a Dad sure does change your priorities around a bit....  Not near as much time to play around these days!

Ref Jim Hunter's post:- If you have it in writing from the dealer that it wasn't your fault, you should be home free.  No court of law will find against you. Kevin,  I find it's easier with grandchildren, I send 'em home to mum. Darren haven't turned on Sky sports yet, i suppose you're murdering us at the cricket?