Well i know mine is alternator related. TO check the electrical system theirs a number of different test you can do depending on what u need to find out out. Like for my GP system i used a charger and a copper pin to test each GP out and found that number 1 was compleltey shorted. For the alternator someone suggested taking the neg. battery cable off and if the lights were still on than the alternator is doing its job. the lights turned off, so thierfor i know its the alternator

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1983 Euro 240D 277K
2016 Mazda 6
Coming Soon, 2013 Mercedes E350 Bluetec
Formers:
2012- Mazda 3
2007 Outlander- complete pile
1995 E300 Diesel 208K
2007 VW Passat 2.0T 63K SOLD
2003 Jaguar X-type 3.0 Sport Sold 04/11 w/88K
2009 Lexus RX350 9061 miles. Sold 04/09
2008 Mitsubishi Lancer GTS:Totaled Sept.,09 @ 24,000
2003 Infiniti I35 58K Sold
1984 300 turbo diesel 222K