When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I recently went through a huge amount of problems with my 2010 ml350 clearimg them out and getting the car running, but am left with 2 minor provlems the horn intoperative, and the dreaded auxiliary battery problem. I am ordering a new aux battery, to replace the current one as I believe it hasn't ever b been replaced. I believe I also read that it could be a voltage converter module also and I was wondering if this battery has anything to do with the horn,. I cab trouble shoot the horn, fuse to switch to relay leaving relay, voltage at horn then horn bad, I know so little about the workings of this car, I cant help wonder if it gets its horn voltage from this aux battery. I haven't went after it yet, just wondering , Does anyone know?
thagorilla
The purpose of the Aux battery is to provide power to the transmission shifter module.
Ever notice if you turn off the motor after parking, without putting the transmission in P the car does it for you?
That's how. The Aux battery allows the module to stay on and power/control the transmission selector - even if you are having charging or power supply issues in the rest of the system.
Contrariwise, if car is on the side of the road and won't start the Aux battery should be protected from discharging by the system as long as possible, so that you can still put the transmission in neutral and get car onto a flatbed.
Check that the fuses you pulled earlier are in place correctly and powering-up all the relevant circuits.
thanks guys tomorrow Im going to have a detailed look at it, its likely a fuse not in that slot from my previous mass fuse pull trying to avoid the car catching fire.
I recently went through a huge amount of problems with my 2010 ml350 clearimg them out and getting the car running, but am left with 2 minor provlems the horn intoperative, and the dreaded auxiliary battery problem. I am ordering a new aux battery, to replace the current one as I believe it hasn't ever b been replaced. I believe I also read that it could be a voltage converter module also and I was wondering if this battery has anything to do with the horn,. I cab trouble shoot the horn, fuse to switch to relay leaving relay, voltage at horn then horn bad, I know so little about the workings of this car, I cant help wonder if it gets its horn voltage from this aux battery. I haven't went after it yet, just wondering , Does anyone know?
thagorilla
If its a siren horn, it has got its own internal battery which dies in time. Can be replaced. Done that with mine a year ago. It involves splitting open the siren housing which is sealed, not menat to be opened actually. Requires basic soldering skils.
Would not say aux battery has got to do anything with siren horn.
04-21-2021, 11:55 AM
