Saturday just wasn't a great day for my baby. First I got hammered for about 40 minutes in a hailstorm (pea to quarter size); man, it's hard to describe how LOUD that is. I tried to get under an overpass with some success, but still a very scary experience.

Remarkably, the paint seems to have come through unharmed. There are some chips in the paint, but I couldn't tell if they were stone chips or not.

But, the worst was yet to come. After the hailstorm subsided I had to find another way around to get home (Interstate 20 was blocked with debris from two tornados and high water), and on the way home a large raccoon darted out in front of me. It hit in the passenger side fog light area and broke the bumper cover. This was at night, and I made my way home from that point on uneventfully.

However, when I started the car up yesterday to clean the paint to check for hail damage the electrical system went nuts. All turn signals were flashing simultaneously at double speed, the fog lights were flashing opposite the turn signals, the radio display was flashing, and you could hear the sound of a relay over by the BCM chattering.

I cycled power, and everything came up OK. Turned on the left turn signal, and all four lights started flashing double speed, but this time no fog light issues. Turn signal off, everything calms down. Turn on the A/C, and everything starts jumping again.

So, I got to a point where everything was quiet and pulled the codes. There were some history codes with the turn signals, IPC, etc., but there are two current codes from the BCM:

2578 H C (will the H always show up for a current code?)
2583 H C

I went through my manual some last night, but didn't get to the right spot to describe these codes. Any help as to what I'm getting myself into?

TIA, and have a good one,
Mike

 

Damn. Sorry to hear about your trouble. Here are the descriptions from the manual. They are BCM turn signal DTC's.

DTC B2578 Right Front Turn Signal Monitor Circuit

Circuit Description
The BCM monitors the RF turn signal circuit in order to determine the status of the turn signal switch. If the BCM detects an oscillating voltage on the RH turn signal monitor circuit, the BCM interprets this as a RF turn signal ON request from the turn signal switch. The BCM will de-energize the RH DRL relay, which will disable the RF turn signal lamp (which is ON for the DRL), thus allowing the RF turn signal to flash. If the BCM does not detect an oscillating voltage on the RH turn signal monitor circuit, the BCM interprets this as the RF turn signal being OFF. The BCM will then energize the RH DRL relay and continue normal DRL operation. The BCM monitors the RH turn signal monitor circuit and determines how long voltage is applied. If the voltage is applied for longer than expected, a malfunction is present and a DTC will set.

Conditions for Setting the DTC
The BCM detects continuous battery voltage on the RH turn signal monitor circuit.
The condition must be present for longer than 5 seconds.

Action Taken When the DTC Sets
Stores a DTC B2578 in the BCM memory.
No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC
This DTC requires an ignition cycle in order to change from current to history.
The BCM no longer detects continuous battery voltage on the RH turn signal monitor circuit for longer than 5 seconds.
A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
Use the IPC clearing DTCs feature.
Use a scan tool.

Diagnostic Aids
The following conditions may cause an intermittent malfunction:
There is an intermittent short to voltage in the RH turn signal monitor circuit.
The turn signal switch or the hazard switch is internally shorted or is sticking.
The BCM needs to detect voltage oscillations on the RH turn signal monitor circuit in order to de-energize the RH DRL relay. If the BCM detects continuous voltage on the RH turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal DRL operation, and the RF turn signal will remain inoperative.
If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Intermittents and Poor Connections .

DTC B2583 Left Front Turn Signal Monitor Circuit

Circuit Description
The BCM monitors the LF turn signal circuit in order to determine the status of the turn signal switch. If the BCM detects an oscillating voltage on the LH turn signal monitor circuit, the BCM interprets this as a LF turn signal ON request from the turn signal switch. The BCM will de-energize the LH DRL relay, which will disable the LF turn signal lamp (which is ON for the DRL), thus allowing the LF turn signal to flash. If the BCM does not detect an oscillating voltage on the LH turn signal monitor circuit, the BCM interprets this as the LF turn signal being OFF. The BCM will then energize the LH DRL relay and continue normal DRL operation. The BCM monitors the LF turn signal monitor circuit and determines how long voltage is applied. If the voltage is applied for longer than expected, a malfunction is present and a DTC will set.

Conditions for Setting the DTC
The BCM detects continuous battery voltage on the LH turn signal monitor circuit.
The condition must be present for longer than 5 seconds.

Action Taken When the DTC Sets
Stores a DTC B2583 in the BCM memory.
No driver warning message will be displayed for this DTC.

Conditions for Clearing the DTC
This DTC requires an ignition cycle in order to change from current to history.
The BCM no longer detects continuous battery voltage on the LH turn signal monitor circuit for longer than 5 seconds.
A history DTC will clear after 50 consecutive ignition cycles if the condition for the malfunction is no longer present.
Use the IPC clearing DTCs feature.
Use a scan tool.

Diagnostic Aids
The following conditions may cause an intermittent malfunction:
There is an intermittent short to voltage in the LH turn signal monitor circuit.
The turn signal switch or the hazard switch is shorted internally or is sticking.
The BCM needs to detect voltage oscillations on the LH turn signal monitor circuit in order to de-energize the LH DRL relay. If the BCM detects continuous voltage on the LH turn signal monitor circuit, the BCM interprets this as a short to voltage. The BCM will continue with normal DRL operation, and the LF turn signal will remain inoperative.
If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Refer to Intermittents and Poor Connections .

 

Sorry to hear you had a lousy day on the road. I guess your day was second only to the raccoon's....

The "H" will always show up whether a code is current or not as once the code has been thrown, it is stored in history until it has been cleared.

The BCM codes are:
B2578 RF Turn Signal Monitor Circuit (Short to Voltage)
B2583 LF Turn Signal Monitor Circuit (Short to Voltage)

I have heard several people have BCM issues where there was a lot of water/rain involved. I'm sorry I can't guide you any better in terms of why the codes are being set off.
I'm sure some folks will chime in that have had some experience with similar issues.
Scott

 

There ya go! Patches beat me too it while I was typing.
It's great to have gents like him around the Forum.
Scott

 

Patches and Scott,

Thanks for the info. I would have found it in my manuals eventually, but they're a teeny bit bulky to bring in to work.

I'm not sure what it is I'm dealing with. I wouldn't think it'd be water, but you never know. I didn't have any problems until the day after, but honestly I don't remember if I used the turn signals after the 'coon strike.

I'll let y'all know what I find.

Thanks again, and have a good one,
Mike

 

Just to keep y'all up to date. I got up underneath the bumper last night and found that the horn assembly had been knocked loose. I got that tightened down, but didn't get a chance to start the car up to see if that fixes my electrical problem. I also found one 2-conductor connector that was floating free, but I couldn't find anything nearby that it would connect to. Once we get the bumper cover off maybe things will become more clear.

Two of the screws for the passenger side outer air dam are missing: it looks like the impact just pulled the screws right out of the nutplates. The small steel "cage" that surrounds the a/c condensor and radiator and mount the air dam that has the two curved steel prongs that point forward skewered the poor critter: blood everywhere. I just hope I hit it in the head first. What a mess!

And, to add insult to injury, my insurance company (which has taken good care of me for the past 20+ years) said that even though both events happened within two hours of each other, they're considered two separate events, and I have to pay my deductable twice ($500 each).

The individuals I spoke with were (are) very courteous and have recommended me speak to customer service, but they also said that the insurance rules are very specific about these kinds of things, and they weren't very optimistic about my chances. Logical, understandable, but disappointing. We'll see.

I've already got a strong recommendation about a shop to go to for the body work, and an appointment for Wednesday afternoon. I'll see about the electrical tonight when I get home.

Have a good one,
Mike

 

Mike,

If you don't have the auto A/C in your car, that free connector could be the one used on the ambient air sensor for the A/C. If you do, it could have been torn off the sensor in the collision. The illustration below shows the sensor located in the lower passenger front fascia.

Sorry to hear about the insurance woes.

Ed

 

Patches,

Man, do you mine for gold or what? I think that's exactly the sensor that connector is for; it's the right length and placement for it, and my car has manual A/C controls.

Do you know if I've got a chance of the horn circuit providing a grounding path that would affect the fog lights and turn signals?

Thanks again, and have a good one,
Mike

 

As a matter of fact, the grounding schematic shows a commonality for the fogs and horns. They share Splice Pack 100. Here's the schematic for your 2000.

 

Here are your frame grounding points.



And the location of Splice Pack 100 (SP100).

 

Ed,

Well, the electrical gremlins are laughing again. I think I've got the problem isolated down to the logic that changes the lights (internal and external) when the parking or headlights are turned on. That's what's causing the flashing effects I'm seeing. There's some relay over by the BCM that you can hear chattering when the lights are flashing. So, I'm thinking that either a relay is sticking or the BCM is screwed up (maybe water intrusion?) and generating an oscillating signal to the relay. When you turn the parking or headlights on the flashing stops, although both turn signal indicators are illuminated all the time.

But wait, there's more! This morning I was driving the car to work (about an hour drive, dropping it off at the body shop today), and about 45 minutes into the drive, out of habit, I used my turn signal (which gets back into the double speed flashing with all four corners flashing), and it worked normally.

Haven't had a problem since. So, either the BCM dried out and magically fixed itself (doubtful) or the relay unstuck itself (IMO more likely).

Thanks for all the help, and have a good one,
Mike

 

things will work out.