The auxiliary battery relay is controlled by the battery control module. If this reading is not zero, then there is a parasitic draw on your system.

I'm trying to figure out why my interior lights is dimming with a strobe effect and notice my RPM is fluctuate by little (vehicle have 105k miles) and when it does the car shakes a little. Absorbed Glass Mat (AGM) batteries are sealed and you don’t need to worry about leakage. After starting car it slowly goes from 13.5V down to about 12V and then I shut car off because I don't want to charge battery again.

When facing the engine from the front, you will see the relay to the right of the HVAC vent. This will result in a decrease of alternator output. Mercedes-Benz does not advise load testing the factory AGM (absorbed glass mat) batteries. If it's the battery can I go aftermarket or do I have to stick with Mercedes? The starter battery is good (bought 2 years ago), the rear batter is at 50%, and he alternator is charging at 14.3V. This tester measures battery conductance by inducing a small A/C voltage into the battery and then reading how the battery's current responds. The battery control module communicates on a CAN (controller area network).,, Auto Parts -, For Every Part of Your Life, VerticalScope Inc., 111 Peter Street, Suite 901, Toronto, Ontario, M5V 2H1, Canada. It's 8 years old and have 105k miles.

Wayne R. Dempsey, Nick Czerula If there is no continuity, the fuse will need to be replaced. The STAR diagnostic tool has a test designed to determine if the relay is correctly working.

I have asked them to check battery voltage. This will also be a good time to inspect the condition of the battery terminals for loose connections and corrosion.

This is accompanied by a red warning screen in the center instrument cluster display that shows a battery accompanied by the phrase "visit workshop.". For a better experience, please enable JavaScript in your browser before proceeding. I'm wondering if mine has 2 batteries, only problem is that it, or they, seem to reside in the cellar below the drivers seat! I had my mounts replace I'm getting ready to replace the spark plugs/wires and all the coil packs. Buy cheap Car Battery for your MERCEDES-BENZ W212 online on the site Follow these steps to view it: Once you start your vehicle, the voltage level should read between 13.8 volts and 14.8 volts. High-quality Starter battery for MERCEDES-BENZ W212 and other models.

Not to worry. Sorry. The following steps are listed from easiest to hardest to perform. Read through this how-to article, and see if it's something you can fix yourself. The voltage regulator keeps the charging system's current flow at the proper levels. went from 12.2 up and stabilize at 13.2. but it drives fine with no issue (drove it around 30 miles). Drove carefully in 1st gear for about a mile. It is designed to read and convert the voltage supplied from the batteries, then read the output voltage to determine if the alternator's output is correct. The F32 is located in the interior on the passenger side footwell area. You go to start your Mercedes-Benz, but it shuts right back off. It's 8 years old and have 105k miles. To determine whether or not your problem is with the battery — without going to the expense of buying a brand new one — use another car to jump start your Mercedes. These codes will save diagnostic time by pointing you in the right direction. Follow these steps to complete this: You will need to locate the multiple fuse boxes in the vehicle and test each fuse to find which circuit the draw is located on. Check the earth strap is secure/has good contact against the battery AND the body/chassis. 2b) It should stabilize at about 14.2 vdc. I have the same problem and, the same problem with my 03 W209. Wait twenty minutes after the key has been removed from the ignition. If you have a wiring diagram available, you can locate the power and ground for the module and test that both are present. All glitches are now gone I suspect the battery must have had some sort of intenral problem that reduced its voltage without substantially reducing its ability to put out lots of amps. Mercedes c class c22 cdi bluetech amg line premium plus Location lighting not working. Why Does My Battery Keep Dying? You are using an out of date browser. I got the battery/alternator light on the dash and checked the main battery to see the voltage and it wasn’t 12.5 not running. An analog meter is much easier to use when diagnosing brief voltage spike or fluctuations. The current voltage level will now be shown. The "hidden" menu is there on all W209's. [Baffled], CURRENT: 2011 SL550 FORMER: C300, ML350, CLK550 Cabriolet, C240, ML320, 300TD. As noted above, a battery replacement will frequently solve this problem. The Mercedes-Benz E-Class has one main battery in the trunk and an auxiliary battery in the engine bay.

When it is started the voltage seems to go down and I took the alternator out and had it tested at advanced autontoday and it … If you tested the auxiliary battery and it passed, you have an indication of a faulty auxiliary battery relay.

May just well do that. 2) No combination of turning key and pushing reset button 3 times will display voltage on cluster. Disconnect either the positive or negative battery cable (you will do this for each battery) and place the positive lead of your DVOM on the battery post. The battery control module is located in the trunk next to the battery and spare tire. 86 meters long and 1. part number: a1665420418 Mercedes E Class W212 engine warning light - this light will stay illuminated if there is a malfunction within the engine after start up - we would advise you to use the iCarsoft MB V1.

Wet Cold Weather, Bat's just hate it, either place it in trickle charge overnight on a battery charger and try that, and 99% solves and saves you the cost of a new Battery, or just go and exchange it for another. Hyperlinked in the discussions section at the bottom of the article is a list of fuses/relays showing their associated circuit and amperage rating. Repair Mercedes Benz Electrical Ignition System. Well the batteries are very important in our cars,in your case I would suspect it is the battery in the boot,starting is a joint effort by the batteries,as far as I am aware the back battery heats up the glowplugs the front battery cranks the starter,just a month ago I had problems with batteries now my front battery was the original,10 years old,so I thought it had to be that as I knew that the back one had been changed about 4 years ago,I used Tanya batteries and bought a replacement,on taking the old battery out I tested it and found it charged but I put the new one in and it was being charged at 13.2 amps so the alternator was good,,things were still not right so I bought a new rear battery,this has made a big difference,things electrical in the car are working so much better,a real curved ball that this new battery may have cured is that my car has occasionally stuck in a low gear so plenty of revs no speed,it seemed to dislike a fast approach to a roundabout the slow down then the acceleration away,I have used that road road 6 times now and the car has not stuck in gear I should note no faults registered by star,the other give away is what happened to you I could drive about 20 miles and stop and have the radio on and it would shut off after about 5 mins,all this points to the back battery.