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for the first time ever, my 2013 GL450 wouldn't start - slow cranking. Hooked up a jump box and it fired up instantly. While testing the charging amps however, I was only getting 6-7 amps. Shouldn't this value be around 60 amps? Or does this mean that the battery is sufficiently charged and so it's not really needing to draw many amps from the alternator? It's pretty odd, and the car now starts as if nothing had ever happened. But I'm carrying a jump box in the car now (they're very small, I think it's an essential tool now, just like an air compressor), and am wondering if the regulator on the alternator is dying.
Last edited by kismetcapitan; 11-19-2023 at 05:09 PM.
The voltage regulator in my 2013 GL450 died on me this year. No warning, just stopped working when I was out of cell phone range, towing a travel trailer. I had not been tracking my charging voltage or current, so I don't know if it was slowly getting bad or not. I never had a hard start situation. The red battery light came on, letting me know the alternator wasn't working. The brushes had worn down in my voltage regulator, so I put in a new one (once it was towed home) and it's been fine since. I don't know if there is a good way to see if the voltage regulator is about to die, but if yours is original then it might be time to change it. They are wear items, they will need to be replaced eventually. It was a little bit of a pain to change the voltage regulator, but it's cheap and I was able to do it from underneath the car without completely removing the alternator, I followed the instructions where you disconnect it and rotate it in place without disconnecting the hoses that are in the way. If your battery is old, it may be time to change that as well. Don't forget your auxiliary battery, too.
That is not how you normally check alternator. Your working voltage should be higher than 12 volts. If it is so - it is working. The amperage usually depends on amount of load.
for the first time ever, my 2013 GL450 wouldn't start - slow cranking. Hooked up a jump box and it fired up instantly. While testing the charging amps however, I was only getting 6-7 amps. Shouldn't this value be around 60 amps? Or does this mean that the battery is sufficiently charged and so it's not really needing to draw many amps from the alternator? It's pretty odd, and the car now starts as if nothing had ever happened.
But I'm carrying a jump box in the car now (they're very small, I think it's an essential tool now, just like an air compressor), and am wondering if the regulator on the alternator is dying.
A: Battery stats B: CEL !!!
-- A : The battery voltage shows a perfectly working charging system. Amperage show battery level is charging well nearly full.
-- B: this is your check engine light aka. "money light". Either visit your local MB specialist or scan yourself.