Silver Box next to fuse box-passenger side
 

There is a capartment on the passenger side floor board that when remove exposes the fuse box and a silver box next to it. Can someone explain what the silver box does? I'm having some funny electrical/starting problems and when foot pressure is placed on the area of the carpet on the passenger side it fixes the problem for a while.

it's the bcm.check the car for faults.it's responsible for most of the body functions including starting,windows,interior lights,etc

Welcome to the forum! :thumbs: It is very common in these cars if there ever has been moisture in the floor from leaks (leaks are also very common) or what ever the BCM will be damaged. Forum member "Bill Curlee" is an expert on this type of damage as well as C5 electronics. Hope he chimes in on this thread. He will probably be able to tell you exactly what to do to fix the problem. He has even made offers in the past to some of the forum members to attempt to fix their BCM for them for free! Since you can temporally fix the problem by pressing on the BCM then it is a good chance it can be fixed. The problem is normally corrosion damage inside the BCM caused from water in the floor area. If Bill don't chime in on this thread send him a PM, I'm sure he can help with this problem.

BCM = Body Control Module. It is a major part of the car. Think of it as the computer that supervises all the other computers in the car. Therefore it has a little to do with a lot of stuff!


If you look it up in a dictionary you will see this definition: :D

BCM (Body Control Module)
Pronunciation: 'bä-dE k&n-'trOl 'mä-(")jü(&)l
Function: noun
1. A small over priced electronic device used in the heart of the electronic vehicle control system in a C5 Corvette which due to poor GM engineering was mounted way to low in the passengers foot well causing it to be easily damaged by water which commonly leaks into the passengers foot well from many sources due to poor GM quality control.

:lurk:

Man....you sure got that right... :thumbs:

:lolg: :lolg: :lolg: :lolg: SPEEDYZ you made my day! That definition made my day!!!

Yep, it's the root of many evils. The best thing that you can do is read your codes:

This is the absolute best C5 Code web site!!!

http://www.corvettedoctor.com/index.html

http://www.corvettedoctor.com/index-1.html

http://www.corvettedoctor.com/Code_Main.html

The sound effects are cool too!!

Once you read the codes, post them here. Please make sure that you include if they are current or history.

If you have not ever read and cleared your codes, you may want to write all of them down, clear them and drive the car for a good long test drive. Read the codes again and see if the DTC codes come back.

Here is what is inside your BCM

http://img.photobucket.com/albums/v4...picsfront2.jpg

http://img.photobucket.com/albums/v4...turesback1.jpg

What exactly are your symptoms?? Please be a little specific. Please include what year car that you have and any other amplifying info.

Bill C

Great stuff guys, you should start your on TV show....

Symptoms are as followed:

1. When you turn the key you can hear the fuel pump going, but nothing else, car is dead.
2. Key FOB does not work on hatch, but does lock and unlock doors.
3. No interior lights.
4. Security system does not work.
5. Instrument panels are dead and do not light up when you enter car.
6. Radio does not work
7. Head lights work.

It doesn't happen all the time, but latley it seems to be getting worse. When I get the car started by pressing the BCM I do not receive any abnormal codes on the DIC.

Apologies, I do have DTC codes and here they are.

SDM
U1000 H
U1096 H
U1064 H

Radio
U1064 H
U1096 H

LDCM
B2252 H
B2282 H
B2284 H
U1255 H
U1064 H
U1016 H
U1096 H

IPC No codes
BCM No codes

PCM
?1626 H

RDCM
B2283 H
B2285 H
U1255 H
U1016 H
U1096 H

RS
C1225 H
C1288 H
U1000 H

RFA
C2110 H
U1000 H
U1255 H
U1004 H
U1096 H
U1016 H
U1064 H

clear them out.they are all history codes,most are for communication loss

Your problems seem to be centered around the BCM. There are two connections on the BCM. Have someone start the car while you examine and wiggle only one connector at a time. See if you can narrow it down to a specific connector.

BC

Better yet, unplug the connectors, and look at them. If they don't seem damaged, plug 'em back. As with all computer plug connections, this breaking of the circuit, so to speak, can often dislodge any particles between the connections and fix your problem.

Just thoughts.

Electrical ISSUE: Grounded Out Interior FUSE BOX-HELPtak
 

Electrical HELP Required…

I have a C5-99. I purchased this with only a few issues and fixes need. My PROBLEM is related to a replacement of an aftermarket “Rocker Switch” that was installed by previous owner to drive some LED-Interior Lights strips and was not working. Here We GO!

I pulled the switch out of the center console and there were three (3) wires as follows:

1) Load
2) Supply
3) Ground/Earth

I disconnected all three (3) and laid them by the console, while retrieving the new switch replacement on my workbench. When I got back to the car…(only about a half a minute) I noticed a light cloud of smoke on the passenger floor board and was getting thicker. I scrambled to the tool box and got a wrench and as quickly as I could… discounted the battery. Felt like forever!

Now here is what I found under the passengers floor door. I located the “Fuse Box” and removed the cover and the positive (+ Hot wire) was connected directly to a 10amp fuse on the bottom “Left” …with no additional jumper fuse and holder. It was hooked up direct to +++. The “GROUND” wire was connected to a screw at the bottom of the “BCM” where there is a little metal tab extended from the bottom. So what I think happened is when I disconnected the “Console Rocker Switch – Add-On … the two wires… Ground and 12V wire touched each other when I exit the car and Grounded Out the “Fuse Box”.

So here are the symptoms. The car dash light do come on and “Service Engine Message” in dash is present and Car Won’t Turnover or start. When I check the battery… still have 12 + Volts at the battery. The wire that feeds the Fuse Box in the car on the passenger side on the top post is only reading 3.2 V. When I take the wire feed “OFF” the post I have 12V again and when reconnecting it drops to 3.2. Hummm

Trying to figure what has failed and trouble-shooting as follows:

Disconnected the top three (3) smaller plugs on the Fuse Box. Still 3.2V at supply and post. Discounted the harness with the “Blue Base Plate” and just below the 3 three smaller plugs on the Fuse Box on top in the # 1 position and Bingo… back to 12V when unpluged. Reconnected that harness and the voltage drops to 3.V again at the supply post. I also checked the 2 two additional harness plugs (2 & 3) below the top large Blue connection and they seamed not to make any difference on voltage. It appears to be the top 'Blue" plug reduces the voltage when plugged into the Fuse Box.

Do I have a shorted out Fuse Box and or any suggestions moving forward. Many thks

Sounds to me like you found the culprit. You mentioned smoke, but you did not mention any melted wires. Whenever there is smoke, something has to be burned. Did you trace the wires going into that blue plug? I am out of town, away from my car, so I can't look to tell you where they go.

Thk You for your response. The Blue Plug is part of the wiring harness and under dash. towards the right of Fuse Box. This is the plug that connects into the Fuse Box with all the little pin connectors. There are 3 plugs of this sort that connect to the Fuse Box and are ALL part of a larger harness. Now to answer your question. No... I did not see any burnt wires at the plug ends and you can only see a very short amount of wires, because they are all wrapped in electrical tape. The smoke from from the area of the passenger floor mat.

From my outline... we know the hot was direct to the Fuse Box with NO external breaker fuse and was always Hot. We also think the ground touched the hot wire, which in turn would try to ground out the 12V in the Fuse Box. Is it possible that we don't have wires burnt and the smoke was coming directly from the Fuse Box and it's plastic housing and components. Just asking

We know that when plugging the Blue Harness plug into the Fuse Box we than shortout the box. Can this be a direction... Shorted out Fuse Box...??? Cause this was what got spiked by the Ground Wire... Thks My Friend!

I guess at this point you are praying that it's the fuse box, and not the BCM. What I would do first is check every single fuse, because if you find a blown fuse, replace it and it blows again, at least you have somewhere to start looking. Food for thought:

1) Can the connectors at the BCM be safely disconnected one at a time while you perform your test of the voltage at the fuse box power feed?

2) Some of those wires go through the firewall. It might be worth pulling the battery and tray, and looking. I once had a mouse/rat chew through some wires under there causing my car not to start. There are 1 million wires under there all of which are black, if I recall correctly. Several were chewed, and I don't know how I managed to match the severed ends up to their correct counterparts, but I did, AND was somehow able to solder them back together with a gun in that small area. Not saying that this is your problem, but at this point, I'd be looking at wires with the hope that it is not the fuse box or BCM, you know at I mean? Sniff around the wires clusters, both under the dash, and under the battery to see if your nose can help you locate something burnt. Cut off some of that electrical tape if it helps. You can always rewrap.

3) Look up a schematic for that blue connector, and maybe you can at least get to the other end of those wires to test continuity.

4) Have you checked the fuses in the other fuse box, just as a lucky shot? (although the DIC message throws a wrench here)

Thks. I did check fuses in the Fuse box and under the hood with No issues found. All of them were OK. The relays I did not ck. Something in the blue plug reduces the current when plugged into the Fuse Box. I could use a schematic...if anyone has it of the blue connector and what it feeds.

Here is some pictures of what I am seeing.https://cimg6.ibsrv.net/gimg/www.cor...187e0b7130.jpg
This Is The Ground Wire (Blue) and the Direct Hot-Green
https://cimg0.ibsrv.net/gimg/www.cor...76d3ded54d.jpg
The Hot FEED To Fuse Box. Reads 3.2V when connected/// not 12V unless taken Off Of Fuse Box Post
https://cimg1.ibsrv.net/gimg/www.cor...6e91f55bcc.jpg
3- Connectors at Top Of Fuse Box
https://cimg0.ibsrv.net/gimg/www.cor...77996d9fe2.jpg
Fuse Box - Yellow Tape L-Side where Green Hot Wire was located
https://cimg9.ibsrv.net/gimg/www.cor...6fd0dbd64d.jpg
Fuse Box Where Wiring Harness Plugs In. Top is Blue Plug Connector
https://cimg8.ibsrv.net/gimg/www.cor...4cdf6288b7.jpg
Here Is Picture Of Plug Connections To Fuse Box. Top One Blue, Middle Gray and Bottom Green

PLEASE use the DIC and read and post the DTCs that come up. If there are a TON of DTCs (and there probably will be) CLEAR ALL OF THEM and then see what comes back.

List all that come back. MAKE SURE that you include the MOULE BCM-,, The DTC 2233 and the History or Current ( "H" or "C") suffix.

The DTCs should point you in the correct direction. The MAIN 12 VDC Fuse Box FEED (B+) comes directly off of the engine compartment FUSE BOX B+ terminal..
Make sure that the battery terminals are clean and tight and the B+ terminal is clean and tight.

If the add on wires shorted out, they should show signs of heat/bunt insulation.

GET RID of those wires!!!!!!!!!!!!!:ack:

I can give you THE CORRECT place for AUX power and not have to worry about shorting the entire car out!!!:toetap:


Bill :thumbs::cheers:

Looking at the picture, YOU HAVE A BLOWN FUSE somewhere. You just have to find it.

The DTCs may help pin point it. Get some liquid electrical tape and repair those main RED feed wires.

Look at ALL of the BCM fuses. There are at least FOUR different BCM fuses I would also suspect that you may have FRIED your IGNITION SWITCH contact inside the ignition switch.

Some of the BCM feeds come off of the Hot in RUN feed that is supplied by the ignition switch.

Each FUSE has two small TEST TABS on top of the fuse. With the IGNITION SWITCH in the ON position, read EACH BCM fuse test tab to chassis ground and see if you read FULL BATTERY VOLTAGE.

Post your results.

BC

I did ck all the fuses with tester across the top of each and all showed continuity under the hood and in the fuse box on passenger side. Are the BCM's in another location???

I do have a good 12V at battery and also at under-hood fuse box. Than a red wire I think go's from the under-hood to the interior fuse box and it is pushing 12V. Only when all the wiring harness is connected inside the car will the upper fuse box post drop to 3.2V. If I disconnect it from the upper stud on box that is to feed the fuse box, then I have the 12V again. The voltage drop is when I connect the blue harness to the fuse box. I ck'ed all the fuses under hood and in cabin across the tops and they are good, Thks any more ideas please!