Corvette_Ed

My car started throwing 2578 and 2583 codes recently (these are the turn signal codes and I've seen them as both H and C and it is intermittent), and after doing some extensive reading I've found that this could be the result of a problem with either the multi-function switch or the hazard switch.

Does this sound like an accurate assessment, and how do I eliminate one or the other as a possibility so I know which I need to fix?

Corvette_Ed

bump...

lionelhutz

Can you describe the operation of the signals. It sounds like it could be a failed flasher that just stays on.

Quicksilver Vert 01

Another Forum member mentioned being almost out of turn signal fluid, in a recent thread.

http://forums.corvetteforum.com/c5-t...or-clutch.html

Corvette_Ed

Flasher appears to work just fine, and I haven't actually seen the signals working strangely. I just pulled the codes the other day and saw a history on the 2583 and a current on the 2578. I double checked everything last night and all appears to be working just fine, but something has to be causing the codes to appear.

Corvette_Ed

And this (which is misquoted btw) is supposed to be helpful how? If you don't want to help because I haven't had the time nor the money to buy shop manuals yet just say so. Acting like a dick doesn't help anyone, including your own reputation. I'm 1100 miles away from home and having troubles, I don't need the attitude.

oh1vette

maybe you've seen these already:

http://forums.corvetteforum.com/c5-t...o-voltage.html

http://forums.corvetteforum.com/c5-s...and-b2583.html

Corvette_Ed

Unfortunately, yes I have. Neither really help much in trying to determine the root cause, and the only time I see the codes pop up is when I'm driving and can't stop to see what's going on. The signals don't flash quickly as they would if a bulb shorted, and when I test everything after I've stopped I can't find any problems. All bulbs are intact and working just fine, and the DRL housings are both in perfect condition with no cracks or leaking. Water hasn't come anywhere near the car either.

PUMP03

Go to post #6 in the following thread:
http://forums.corvetteforum.com/c5-g...-baffeled.html
There is a pdf with schematics of the Turn Signal Monitor circuit and some diagnostic steps that may point you in the correct direction

Corvette_Ed

That does help Pump, and thank you. I'm wondering why that thread did not come up in the search I ran for the codes that are both mentioned in it. Strange, but then that seems to be my type of luck lately.

Thanks again, you are helpful as always. This will help me figure out where the problem lies.

PUMP03

You probably searched for DTC 2578 in stead of B2578. or some such thing. Searches are not always as "fuzzy" as we would like them to be.

lionelhutz

It's odd you think the signals always work yet the codes appear. Basically, the signal wires from the signal switch to the circuit for the front lights are monitored. If either stays on more than 5 seconds you get the corresponsing code. The wires are the lt blu and dk blu at the multi-function switch connector pins F & G or triangles D and B as shown in this schematic. Those 2 wires go into the circuits shown in that pdf in the thread PUMP posted.

Corvette_Ed

It's not that I think they always work, it's more that I have not seen them working strangely, such as the turn signal indicator flashing quickly on the IPC, even yesterday when I had a 2578C thrown while I was driving. Of course I was on a road that has nowhere to pull over so I could not get out and check.

lionelhutz

Hmm, the code appeared while driving down a road without you signalling? Or, you checked for the codes while driving down the road and found them but they could have been generated during some turning or stopping you were just previously doing? Do these codes even cause a CEL or sevice warning? If it's happening when just going down a road then it would indicate you have some kind of short on those wires to a power source.

I believe the dash indicators tap off those wires as well, so you should be seeing them stay on for a 5 second interval to get the code. I'm not positive though, I'd have to search for wiring diagrams to find the exact source of the indicators. They typically come of the front turn signal wiring though and they can't come off the bulb side of the relay because they'd be on with the DRL. They can't come off the rear wiring because they'd come on with the brake lights. So, the only place to tap power for the indicators is those 2 wires.

Quicksilver Vert 01

The first place I would look for that intermittent wiring short, is the lamp sockets and wires in the corner housings.

The DRL's generate a lot of heat! The lamp sockets, and the insulation on their wires, will often melt and short out over time.

The heat from the bulbs will also melt the area just above them, on the plastic corner housings, which can allow water intrusion into the housing, which can cause an electrical short in the bulb sockets.

lionelhutz

The power for the DRL's doesn't come from the wires that are monitored.

Corvette_Ed

The second one. With all of the problems I've had, and on top of that being in another state, I've made a habit of checking the DIC regularly for codes.

No, nothing to indicate a problem other than the DIC codes. If I hadn't checked for codes I would never have known the problem existed.

There's nothing on the dash to indicate a problem. Turn signals go on and off just as they should.

Corvette_Ed

What does that mean in layman's terms? Is this something I have the possibility of working on without needing to get the car in the air to get underneath? If I have to get underneath I have no choice but to wait until I get home in the next week or so.

lionelhutz

It means that with the DRL's on that power should not be back feeding into the 2 wires that are monitored.

Quicksilver Vert 01

You really need to lighten-up a bit, and not get so defensive here!

The reference to "getting low on turn signal fluid", in the thread that I linked to, was meant to be humorous. Most others here would certainly see it that way, and get a good chuckle when reading it.