Updated 3/27/2021 & 5/5/2022 - A look at the 2020 GT500 and exhaust system valves

[Tomster]

The harness is reasonably short.

I didn't find the harness itself in the wiring diagrams, but it looks like it did recommend a pigtail kit for that application. The harness is listed as 14b599. I couldn't get much more info based on that.

If I were him, I would avoid the pigtail kit and repair what I have.

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[AMBJR]

I've seen zero data on the matter. Just an occasional complaint that sometimes points to a valve that is sticking. I'm not a Facebook fan but I have seen a few 2020 GT500 complaints regarding the system along with mention of damaged harnesses and blown fuses. My sense is that it is typically higher mileage cars that see valves sticking and I think this mirrors what GT350 owners have seen.

That is why I changed out my stock cat back to a MAGA FLOW 3" non valve system!!!

 

[Epiphany]

I didn't find the harness itself in the wiring diagrams, but it looks like it did recommend a pigtail kit for that application. The harness is listed as 14b599. I couldn't get much more info based on that.

If I were him, I would avoid the pigtail kit and repair what I have.

I'd buy the harness and repair what you have and keep it as a "just in case" extra.

Tom, you were right on the part.

Surfergeek, note the damage someone else had with the same problem and how closely it replicates what you show in your photos...

 

[Surfergeek]

That is what I was getting at earlier in the thread. My harnesses were tight, with no strain relief, and too close to either the exhaust or to edges that could chafe or cut. I yanked some of the pushpins, rerouted and ziptied it for better clearance all around. Glad you found the issue.

At initial inspection without pulling down the rear diffuser it looked okay and wasn’t visibly rubbing but after getting it back from the dealer after they changed the actuator it was clear it needed a closer look.

 

[Surfergeek]

The harness is reasonably short.

It is indeed with connectors at both ends.

relatively easy replacement. The dealer has already ordered the part and will change under warranty.

 

[Surfergeek]

I'd buy the harness and repair what you have and keep it as a "just in case" extra.

Tom, you were right on the part.

Surfergeek, note the damage someone else had with the same problem and how closely it replicates what you show in your photos...

I had not seen that. That’s it exactly.

 

[mmburr88]

Commenting so I know where to find part numbers to convert my '19 GT to active exhaust. Please continue your regularly scheduled shenanigans.

 

[Tomster]

The body shop had my bumper off so I asked them to take photos of my exhaust harness.

So I don't see what the harness would be rubbing against and chaffing.

 

[Epiphany]

Last photo.

Note, the system "grows" with temperarure and the greatest amount of overall movement or elongation occurs at the end, where the mufflers reside.

 

[Strokerswild]

Has anybody started a list of things to check on these upon delivery? Seems something might be a good sticky down the road.

First it was the heater hose routing, now this potential wiring headache. Horrible fit and finish is known across the Mustang line, so that shouldn't be an item....

 

[Snoopy49]

I was surprised to see a lack of a wiring strain relief near or on the connector.

 

[Tomster]

Has anybody started a list of things to check on these upon delivery? Seems something might be a good sticky down the road.

First it was the heater hose routing, now this potential wiring headache. Horrible fit and finish is known across the Mustang line, so that shouldn't be an item....

How about everything?????

 

[Surfergeek]

In the latest installment of as the actuator turns ....

Went in for repair work to replace the harness today, for those wondering, they ordered and received the entire pig tail.

After further evaluation, they determined the actual valve in the exhaust was binding.

So I will be having the entire exhaust replaced and new wiring pig tail installed when the exhaust is replaced.

So in summary:

Initial inspection (without removing rear diffuser) all wiring looked okay.

Lubricated as best as possible with exhaust still on vehicle and it worked for a little bit.

Warning light came back.

Went to dealer, they replaced the actuator on the passenger side.

Worked for a little bit. Warning came back.

Inspected myself, found that the wiring harness was frayed, with 3 of the 4 wires exposed. Isolated and wrapped each wire in electrical tape.

It worked more reliably, while waiting for the harness to come in, but would still get the error on occasion.

Came in to have the pig tail replaced, and they determined that the actual valve was binding as well, which necessitates replacement of the entire exhaust since it's 1 piece. Will go back one more time to have the full exhaust replaced and wiring harness replaced, and then hopefully the ordeal is over.

So if you are having this issue, it could be multiple issues all at once.

I had - frayed wires from rubbing on the pinch weld and a bad valve that was occasionally binding, the actuator was replaced, but I doubt that it was actually bad after seeing the other issues.

 

[Surfergeek]

Hopefully the last update for me:

Today they replaced the exhaust, replaced the pig tail, and I confirmed the wiring harness is not strained as it was installed so hopefully issues are behind us. I do plan on getting some additional heat shielding wrap to give it one more layer of protection.

 

[Grant4514b]

FYI I removed the Grimmspeed exhaust valve simulators and pigtails from my 350 and installed them on the 500 to keep the exhaust in track mode all the time. Seems to be working fine but haven’t been able to drive it yet to see if anything pops up. Right now if I hit the valve mode button I get a message saying not available. You should be able to leave the car in any mode you want at all times by using one of these on each side.

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