Hi everyone. I won the dreaded early c5 wiring lottery.

I have several dtcs that appears and the. Disappear but also many physical symptoms. When I turn off my ignition and pull out the key, the radio turns off and then back on right away. Every time I turn on my headlights l, it’s a guess to whether the left one lifts up, the right one or they both lift, or neither lifts up. Lights turn on all the time. Also the windshield wipers have a stiffer mid way down on the intermittent setting but work fine on low and high. If I leave the battery connected to the car it drain over one night period. Sometimes when traction control is on, the engine studders under heavy throttle. The drivers seat sometimes is adjustable with the power switch and other times it is not.
The battery is brand new and I keep it on a float charger at all times. I think it is ebcm related but please help me.

can someone tell me how to test these wires and or grounds to figure out why my ebcm won’t shut down unless I unplug the battery?

I am am considering buying an 01 ebcm, ignition and wiring. How hard would it be to swap those into a 1997? I know the 01 are better but I know resining is required. Has anyone done this swap? Would it be better to swap the computer too? I could buy the engine and computer off the same car as well but again I know I would need to rep in several things and I don’t have some sensors the 01 may have.

i am also considering replacing all the ground packs or cutting them out and soldering in standard ring connectors.

Thoughts?

 

None of these problems are related to the ebcm. The battery drain should be addressed first as it can cause several problems. Any competent shop should be able to locate the battery drain and if you are having problems with the seat switch I would start there. Why don't you just disconnect it (fuses or just pull the connectors) and see if the battery still drains. The lights are likely due to worn bump stops or stripped gears which are easy to replace and available from several aftermarket vendors. When traction control activates it is going to cut power, that's how it works.

Putting a 01 ebcm in your 97 can be done but it would be a major and very expensive project if you could find anybody willing to attempt it. There is a sticky about the conversion at he top of the page.

 

I should have been more specific I guess about the traction control issue. It studders even though there is no loss of traction at anything over about 40% throttle. If I turn it off, the studder immediately stops. I have never seen restroom control react that way in any other car I own.

I took it to two shops and the dealer and none of them have been able to figure it out unfortunately so that’s why I am here still trying to get it figured out so I can enjoy owning a corvette instead of being frustrated

i was was hoping to trouble shoot the short myself but I don’t know how to do that.

 

Use the dic to get the codes and post them. The codes may give people a clue to what is happening. There are several ways to isolate a battery drain depending on what tools you have available. Just search "battery drain in a C5 Corvette". You need to get that resolved first before you go chasing possible shorts.

 

You really need to Tackle the major issues first and like BigGun stated, I highly doubt that the EBTCM is causing ALL of these issues.

I will try to answer some of your questions by injecting replies into your original post The replies will be posted in a different color:

I have several dtcs that appears and the. Disappear but also many physical symptoms. When I turn off my ignition and pull out the key, the radio turns off and then back on right away. The radio will play for approx. 12 min after you turn the ignition off. IF, you open the door, it should shut off. The circuit that controls this is called the RAP "Retained Accessory Power" It will also or should turn the cars interior lights, hood light ect off after 12 min.


Every time I turn on my headlights l, it’s a guess to whether the left one lifts up, the right one or they both lift, or neither lifts up. Lights turn on all the time. Our Steering Column Multifunction Switch (the one that controls the lights) are well known to fail and cause this issue. The head light motors are also both controlled by a Head Light Control Module (HLCM). The head light control module can present a couple of issues.
1. Fails to shut down when the headlights are fully lowered (runs the battery down)
2. Fails to provide the proper drive signal to the head light motors.

The module is sealed with a RTV looking substance on the back of the module and that RTV can shrink/crack and let moisture into the module. Feel the module and see if it is WARM to the touch. If it is, that's an issue Its on the frame under the passengers side headlight. The (HLCM) is expensive so just don't replace it out of a desire to install new parts. Take it out and examine it.

NOTE! You need to learn how to take a Battery Current Draw Test to see how much current that your C5 is drawing when the car goes into the SLEEP Mode. Get a DC AMP Meter capable of reading 10 AMPS and insert it between the Negative battery terminal and Negative battery cable The designed battery current draw in the sleep mode (after approx. 12 minutes of time) should around 20 milliamps. (0.020 amps).

Also the windshield wipers have a stiffer mid way down on the intermittent setting but work fine on low and high. You need to remove the windshield wiper arms and the plastic cowl and inspect the wiper motor and wiper arm mechanism. You also need to see if there is standing water in the wiper motor well. That would mean the drain udders are clogged!!!!!

If I leave the battery connected to the car it drain over one night period. NOTE! You need to learn how to take a Battery Current Draw Test to see how much current that your C5 is drawing when the car goes into the SLEEP Mode. Get a DC AMP Meter capable of reading 10 AMPS and insert it between the Negative battery terminal and Negative battery cable The designed battery current draw in the sleep mode (after approx. 12 minutes of time) should around 20 milliamps. (0.020 amps).

Sometimes when traction control is on, the engine studders under heavy throttle. Anytime the car engages Traction Control, it pops up a message in the DIC. TRACTION CONTROL ACTIVE or ABS ACTIVE etc... When the car studders, see if those messages appear. They don't stay on LONG!

The drivers seat sometimes is adjustable with the power switch and other times it is not. The drivers seat is a big source of battery drain. It isn't just a switch. It has diodes in it that can fail and cause issues along with sticking in one of the seat movement positions. Unplug the seat connector while you are measuring current draw and see if that causes the reading in sleep to drop!


The battery is brand new and I keep it on a float charger at all times. I think it is ebcm related but please help me.

can someone tell me how to test these wires and or grounds to figure out why my ebcm won’t shut down unless I unplug the battery?

I think you are confusing the EBTCM with the Body Control Module which controls ALL the functions that you are having issues with. The BCM is in the passengers foot well next to the fuse box (big silver box) The EBTCM on your car is mounted on the rear of the car behind the differential.

I am am considering buying an 01 ebcm, ignition and wiring. How hard would it be to swap those into a 1997?
Unless you are very wealthy, have lots of time to have your car down, having a shop convert your car to a 2001-2004 EBTCM is NOT an option. Yes, it can be done but is NOT easy! Especially on the rear mounted EBTCM. Most shops wont even attempt it!

I know the 01 are better but I know resining is required. Has anyone done this swap? Would it be better to swap the computer too? I could buy the engine and computer off the same car as well but again I know I would need to rep in several things and I don’t have some sensors the 01 may have.

i am also considering replacing all the ground packs or cutting them out and soldering in standard ring connectors.
DO IT! Unless you are a C5 purist, getting rid of those splice packs will eliminate a LOT of issues. LOL! That's how the C6 grounds are configured. Ground wires in one eyelet! NO SPLICE PACKS for them!!

Thoughts?

I don't normally tell people to just change out parts but, here is one exception. Your Ignition Switch has a BIZILLION ON & OFF cycles on it. Our Ignition Switches are a prime source of electrical issues. The contacts inside get burnt/pitted and frequently output less than proper battery voltage. That's a job you can do your self and it wont break the bank!

Call Me,, PM SENT!!

Bill