Hi all,

I'm having some gremlins going on with my car, and wanted to do my due diligence and check the footwell fusebox. I've peeled back the carpet, removed the metal plate, and removed the two large nuts holding on the red cables running into the fuse box. However, I'm not sure exactly how to proceed from there, and don't want to get rammy and break something due to my incompetence. If anyone could offer any advice, I'd really appreciate it. Thanks!

 

First - Don't disconnect the large cables without disconnecting the battery ground cable from the terminal. Shorting one of those cables directly to ground can cause massive problems...

You want to make certain that the main fuses and their connections will carry the major current loads needed to operate the car. You want to test from the load cable (the actual cable if possible, that is on the car side, not the battery side) to ground/earth. It is much better to test the fuses and their connections by using a test light that pulls several Amps of current flow through the entire string (cable from the battery/connection to the fuse/fuse/connection to the cable to the load). It is absolutely possible to have full voltage, but not have enough Amperage to run the car. (Think of a battery cable that is almost totally broken, with only one strand of copper still connected.) One of the easier ways is to use an old (but functional) headlight as a test light to check from the load side of the connection (furthermost from the battery) to a good body ground/earth. A good bright light is a good indication that a reasonable amount of current is making it through.

Any trace of corrosion or heat damage anywhere on the system requires that you disconnect the battery ground cable (making certain that it can't creep back to the terminal and make a connection) and thoroughly clean every part of the connections.

 

Thanks for the quick reply, and the advice, which I fully intend to take. With that said, how do I go about physically opening that fuse box to see the fuses themselves? Thanks so much!

 

The fasteners holding the aluminum panel to the floor should be obvious - remove them, carefully lift the panel.

 

Hey again,

To close this off, I was able to rectify my issue without opening the footwell fuse box itself. Thanks for the advice nonetheless. Cheers.

 

 

The problem I was having is that my telescopic steering and wipers (and maybe my cruise?) were out. I won't say I found a "root cause", so to speak, but what I did end up doing was disconnecting the connections held onto the footwell fuse box with nuts, and I also removed the left under-hood fuse box and reseated all the connections. I then buttoned everything up and gave it a try, and this appears to have rectified my issue. I don't 100 percent trust that I've "solved" it, but it's working for the time being.

 

Hello all. I have a 2000 s500 with a dead battery.
I used the jump points under the front passenger floor mat but while doing so, there was a spark as if I blew a fuse. However, I was able to put a brand new battery in the trunk. When I attempt to start my car, all lights, radio and soft door close works. When I completely turn my key to crank the car, nothing happens, not even a sound. Previous to this, I would always hear a buzzing sound when I turn my key to the second position. I know longer here the buzz when attempting to start the vehicle. Someone, anyone please help!
It qould be greatly appreciated... I'll post a screen shot as well.

 

You found why those aren't "jump start points". The usual recommendation is to use those connections to apply enough power to the car to open the trunk (if the metal key doesn't work/isn't available), or to hook up a battery charger to charge a dead battery. You now need to investigate how to find and replace the blown fuse.

The rust on one of the connections probably indicates that you have had water under the carpets, usually from a plugged drain in the HVAC plenum under the hood. Such intrusion will cause numerous electrical problems with the connections that you see, as well in the rear SAM under the back seat. There are dozens of threads on the water intrusion problem, and many of those threads will also help you with your blown fuse.

 

Thanks for your reply. I did not use this for jump points. I would just connect the cables so that I could get enough power to open my trunk. I would then jump the car from the battery in the trunk. On my last attempt to open my trunk, I placed the cables on the jump points as usual but this time something sparked as if I blew a fuse. I just can't for the life of me think of how to make my key turn over. I have full power and a brand new battery

 

There are large-amperage "pre-fuses" in two locations:
- Behind the trunk lining forward of the battery.
- Under the aluminum panel under the right front floor carpet.

The best way to test these fuses is with a high-current-draw test light, such as one made from a headlamp bulb, testing for full brightness on each and every connection on the pre-fuses. If you are certain that every pre-fuse and connection is good, then you need to start testing the available power at both terminals of every fuse in all three SAM units. Look closely at the visible ends of the fuses to find the tiny metal spots down in holes. If you have power on one dot, but not the other, the fuse is blown.

 

Your replies are appreciated more than you know, Thx!
I have 2 things that I believe are causing the key to do nothing when attempting to start my vehicle. For one, the jump points under the front passenger floor mat isn't getting any power at all when I connect cables to it. Secondly, I opened the hood and checked the fuses but on the passenger side, it seems as if something was burned but all of these fuses are good. My apologies, I know it sounds weird. Look at the top left 5amp fuse.. Here are two screenshots. 🙏

 

Hi, by any chance, would you so happened to know why my jump points under the front passenger floor mat aren't giving me any power whatsoever? I'm trying to get into my trunk but the jump points will not power the vehicle. This problem has me on my last grey hair. Any help at all would be greatly appreciated. 🙏

 

You should have an emergency metal key inside your key fob - but they aren't that easy to use. The trunk lock is often sticky from lack of use, and you need to push up on the lock as you turn the key. Turning the key one way opens the lock, turning it the other way turns off the power lock/unlock function on the trunk lid.

There is a "pre-fuse" inside the trunk lining just forward of the battery.

 

Did you by any chance get any farther with this. Mine is having the same issues

 

Burned connections or fuse holders are caused by high resistance. Power going through resistance creates heat. The cure is to remove the resistance - usually by carefully and completely cleaning all parts of the burned connector or holder.

 

OP , to charge battery why didnt you just open the trunk with the key. turn and press

lets not forget most people think they cant open trunk to get to dead battery , without knowing how to use the key properly. i have seen people tear off the rear licence plate trim, or thinking you can jump car like this i think is the case. the blade key is all i use for my trunk since my PSE pump doesnt work on the trunk release (havent learned remedy) but i have a draw somewhere so i have to disconnect battery each time i part it for a few days