Melanie,

Thanks for the reply. Since it's my first failure, I am not too worried about it but I am concerned. To replace it, it costs $1.25 plus my labor of 5 minutes. I'll just keep an eye on the problem to see if it happens again. As a side note, they have miswired the positive and negative leads but I have protection for that. The unit works fine after this happens. I'll chalk this one up to the customer damaging it because it worked fine when it l tested it.

Chris