2002 2500 Wiring Short (s)

My 2002 Freight Liner is exhibiting the following issues:

Fuse box 1:

Fuse 1 blows when light switch is turned on.
Fuse 9 blows when inserted.
Fuse 10 blows when light switch is turned on.
Fuse 11 blows when light switch is turned on and engine is running. Does not blow when ignition is off and light switch is turned on. Does not blow when ignition is turned to on and engine is not started. when fuse does not blow front and rear running lights work.
Dash lights come on when ignition switch is on and engine is not started but go off when engine is started.
Transmission is in limp mode - the issue began when the sprinter first blew the fuses. The Dash light issue has been ongoing since I purchased the van this summer.
I do not have a mercedes sprinter code reader.
I have replaced the fuse box (due to another issue). Yes, battery was disconnected during replacement.
I have replaced the multifunction switch. Yes, the battery was disconnected during the procedure.

has anyone experienced some or all of these issues? Can anyone provide guidance to solve the problem, short of a complete rewire of the van?

New to the forum and tried to find a thread on this - found several close but not presenting quite the same.

I am not a mechanic, nor an engineer but will do my best to answer any questions you may need to help diagnose this issue. Please remember that I will not understand many acronyms and professional words, abbreviations and phrases. I am not stupid and can follow instructions, just not experienced in the field of mercedes sprinters. Please respond in plain english. Thank you in advance.

If it's within your budget, I would highly recommend getting an autel AP200 scanner, around 60$ on amazon. It pays for itself in no time. It would also be helpful to list or post a photo of the fuse location placard because fuse locations vary across sprinters. To clarify, fuse blowing issue came up, fusebox 1 (FB1) and the multifunction switch were replaced, and no change?

How did this trouble start?

Did it start after replacing the Multi-Function Switch (MFS)?

Did it start after replacing Fuse Box #1? Or why was FB #1 replaced?

Did it start after some other event, eg washing the inside of the van with a hosepipe (it has been done!)?

Keith.

ssg jimmy said:

My 2002 Freight Liner is exhibiting the following issues:

Fuse box 1:

Fuse 1 blows when light switch is turned on.
Fuse 9 blows when inserted.
Fuse 10 blows when light switch is turned on.
Fuse 11 blows when light switch is turned on and engine is running. Does not blow when ignition is off and light switch is turned on. Does not blow when ignition is turned to on and engine is not started. when fuse does not blow front and rear running lights work.
Dash lights come on when ignition switch is on and engine is not started but go off when engine is started.
Transmission is in limp mode - the issue began when the sprinter first blew the fuses. The Dash light issue has been ongoing since I purchased the van this summer.
I do not have a mercedes sprinter code reader.
I have replaced the fuse box (due to another issue). Yes, battery was disconnected during replacement.
I have replaced the multifunction switch. Yes, the battery was disconnected during the procedure.

has anyone experienced some or all of these issues? Can anyone provide guidance to solve the problem, short of a complete rewire of the van?

New to the forum and tried to find a thread on this - found several close but not presenting quite the same.

I am not a mechanic, nor an engineer but will do my best to answer any questions you may need to help diagnose this issue. Please remember that I will not understand many acronyms and professional words, abbreviations and phrases. I am not stupid and can follow instructions, just not experienced in the field of mercedes sprinters. Please respond in plain english. Thank you in advance.

Click to expand...

Need to trace the circuit for each fuse thats blowing. Probably the easiest way to start would be On the fuses that blow when the lights are turned on, disconnect every light on the van. (Disconnect each light at the harness. Do not just pull the bulbs) Replace the fuse. If it doesn’t blow start plugging things in one at a time. When the fuse blows you know where the issue is. If you can correlate the time the problem started To something you changed on the van that might help you. Like perhaps you added a trailer hitch and pinched a harness when you bolted it up and it finally rubbed through and is shorted or someone wired the harness plug incorrectly.

If unplugging each lighting component doesn’t stop the fuse from blowing I’d remove the drivers seat and remove all the relays I can see. Take some pictures before you do so you know the configuration and layout to put them back


Btw a scan tool isn’t or code reader isn’t going to do much to find a short. Nothing wrong with having access to live data on your van though. Finding shorted circuits takes time consuming old school hands on testing.



I’m under the assumption you changed the multi function switch because of this issue?

Are you speaking of the fuse block beneath the steering wheel, or the fuse panel on the side of the driver's seat?
(i'm assuming under the steering wheel, but this has been a confusion in the past...)

The 2003 (and 2006) service manuals are available here: http://diysprinter.co.uk/reference/
The 2006 is 98% correct for the 2002, just use the "except OBD" pinouts for the ECM connectors.
2006 manual: http://diysprinter.co.uk/reference/2006-VA-SM.pdf
The 2006 also has better (more complete) locator diagrams in section 8W-91

My 2003 manual does not assign a fuse to position 9 in the steering wheel panel.
The inside of the cover for the fuse panel should list the fuses' functions ... what does it say your failing fuses are for?
(to verify that the service manual and your van match)

Looking at one example:

Dash lights come on when ignition switch is on and engine is not started but go off when engine is started.

Click to expand...

That's a classic symptom of a broken ground connection ... one of the brown wires not making it to its usual bolt to the sheet metal.

Does you van have the Daytime Running Lights (DRL) option?
(if you don't know, you can enter your VIN to https://www.datamb.com/ and fetch a free copy of your "datacard".
That's the full list of what MB built into *your* sprinter.
If you have DRL, that puts a number of additional relays and wiring into the mix.
---------------
In my 2005, Fuse 1 (under the steering wheel) is/are the right-side parking lights (fuse 11 is left side).
My fuse 9 covers the hazard lights, the instrument cluster electronics and the turn signals.
My fuse 10 is the instrument lighting
My fuse 11 is (as above) the left side parking lights.

Wire damage (a rodent chewing through them) can cause all sorts of puzzling havoc, since it can short-circuit things together.
Another weak point in the Sprinter's wiring is where the harness makes a sharp bend behind the fuel filter.
Snip the plastic strap that's holding it (too tightly) against the engine block and "ease" the bend (flex it to less of a sharp turn) and see if the symptoms change ... if they do, then suspect damage to the wires inside the bundle due to rubbing.
If you think that's happening, you can slit the external wrapper and look at the wires themselves (bring a flashlight).

--dick

Thank you for all the responses!

koenb: I have ordered the autel AP200 scanner. I will have it tuesday. it is currently on sale for prime members for 50.99 and free shipping. fuse box is the one under the steering column. no changes to issue after replacement of fb1 and multiswitch.

Keith: How did this trouble start? I purchased the van in September 2019. already had some issues: dash lights, in dash cig lighter not working. poorly installed radio (would randomly loose electrical connection), front dome light works - rest of interior lighting did not, door connectors for sliding side and rear doors not working (the copper "buttons" that make contact when the doors are closed), mechanical issue with sliding door, electric locks are very screwy - if a door is locked and rest are unlocked it will lock the unlocked doors and unlock the locked doors, etc. all head lights, tail lights, blinkers, hazards, daytime running lights, brake lights, etc. worked. antilock brake sensors are coding and need to be replaced. I have the parts but as my van will not fit in my garage I was waiting until the snow melts to replace.
VAN HAS ADDITIONAL WIRING: wired for electric brakes. have not pulled a trailer with brakes so don't know if it works but using an adapter for a small boat trailer all trailer lights work. Van had air shocks with mini compressor and under dash control - it has no air shocks now and I removed the under dash controller when I replaced the multifunction switch. an aftermarket set of cig lighter plugs were added (not professionally and not a good splice job). these have been removed and wires properly terminated and sealed off. Van had a wheelchair lift in the back that was removed. after problem began I disconnected all of the lift breakers, fuses, relays and wiring. It has made no difference.

Did it start after replacing the Multi-Function Switch (MFS)? Before. I ordered the mfs because, after review of wiring diagram, and because of the instrument cluster light, i thought that was the problem. made no difference

Did it start after replacing Fuse Box #1? Or why was FB #1 replaced? Yes. all of the other wiring from previous owner was haphazardly added to the fuse box which had caused problems with other fuses that are not the problem now. Current problem did not start until about two or three weeks after replacing fb#1. However, one other time, prior to replacement, wife was driving and van went into limp mode. (I, of course, dismissed it at the time thinking she had placed the van in second gear and didn't know it.... ). Now I see that that may have been an early warning sign...

Did it start after some other event, eg washing the inside of the van with a hosepipe (it has been done!)? No. We got the van so that we would have a comfortable vehicle to take trips with my daughter (she has cerebral palsy and uses a power wheelchair). We did general mechanical maintenance to the vehicle and drove it to Michigan to see our grandchildren for thanksgiving - we had no problems other than driving home in a blizzard.

jrod5150: thanks for the tips on tracing the circuit for the short or shorts. Yes, this issue is why i replaced the multifunction switch.

Dick: Yes, i have dtr. My 2003 manual also does not show anything for fuse 9 but the wiring diagrams show fuse 9 from fusebox 1 connected only by plug connections (no exposed wiring connections at all) to the multifunction switch. that is why I replace the mfs - all of the blown fuses run through that switch and the dash lights do also. I will get a copy of the 2006 manual it sounds like it will be helpful. thank you for your info.

Thanks for the reply,

Manuals can be downloaded from the links in many of our signatures...

Sprinter reference info site http://diysprinter.co.uk/reference/


Keith.

Thanks for the added info. Stereo basic installation, if someone cut the original connector instead of using a harness adapter they may have used the illumination lead for the dash wiring as a ground for the stereo, that wire will test 12v ground when the lights are off but when you turn the lights on it will become 12v positive and short to the stereos ground through the antenna which grounds the case. Unplugging the stereo will eliminate it for testing purposes. Same with your cigarette lighter add ons. There’s 3 wires in the factory lighter connector. A positive (red/yellow), a negative (brown) and the illumination wire (grey I think) btw I’m a tad color blind but those colors are easy for me to distinguish the difference.

Bad stereo installs can cause some crazy stuff to happen...

Midwestdrifter said:

Bad stereo installs can cause some crazy stuff to happen...

Click to expand...

Oh ya! it’s why I always spend the $8 for a harness adapter. Can’t stand seeing hacked dash wiring. When chasing a short, I always start by disconnecting anything aftermarket.

on my 2002 sprinter the main wiring harness that goes through the firewall got seriously abraded and worn through from contact with the steering column. It caused all kinds of problems.