Our 2004 Crossfire has been trouble free for about two years (20,000 mi).

About a month ago the BAS/ESP light came on intermittently. This happened about once a week. The cruise control also would not work. Now the Brake Lamps are on all the time. The iCarsoft meter reads "C1207 S9/1 Stop Lamp Switch A7/7b BAS Diaphram Travel Sensor Implausible Signal From Component."

Does anyone have a similar experience, or a suggested troubleshooting sequence for this problem?

Thank you
John

 

 

Thank you for this suggestion. I will begin troubleshooting at the stop light switch, and replace the switch if there appears to be a problem. I am assuming that if the stop light switch has failed (on state), and I unplug the switch connector, the stop lights should go out.

 

The stop light switch does more than operate the brake lights. It is also involved with the BAS/ESP system.

 

 

Thank you for this information. The picture helps identify the proper part, and the schematic helps a lot too. It clearly shows there are a lot of interconnections between the Brake Light Switch and Other Systems. I am also getting a bunch of other stored trouble codes: P1876-Traction System Communication Failure, P1817-Back Light Short, N49-Steering Angle Sensor, B1040,B1041-CAN Communication faults to Engine Control and Traction Control Modules. This information helps explain why I could be getting these seemingly unrelated trouble codes.

 

I'd change the switch, maybe the relay as well.

If things still act odd, I think I'd look the battery terminals over, clean them, check the condition of the battery ground cable connection to the chassis, verify the jumper from engine block to chassis is healthy and if I still have issues, replace the battery. Or at least keep it in the back of your mind that the battery may be going...

 

 

I opened mine up and this is what I found when I bent the points open:

 

Thank you for this advise. I will replace the Stop Lamp Switch, if that doesn't solve the problem I can swap the relay out from my other car to see if that helps. I will also check the battery and connections. And this is a good thing to do anyway with winter coming. I already have a brand new Die Hard sitting in the garage on trickle charge.

I really appreciate everyone's help and advise. What a great car, and a terrific Forum. Thanks!

 

Thank you. I will sure be happy, if it is only a switch. I have obtained an IDI brand switch for $22 at OReilly's here in Fortuna. It isn't exactly the brand I prefer, but it fits Crossfires and Mercedes, and should work. It is usually hard to find any Crossfire parts in my area, especially on Labor Day. I also ordered a Mercedes switch from FCP Euro for $11, but it will take awhile to get here. I can swap it out later, and keep the IDI for a spare.

 

Wow! Thank you for the photo. This switch is really in bad shape. My Crossfire has about 52,000 miles on it, but I guess the switch could go out that soon. I have obtained a new switch and will swap out the old switch. If that works, I will also take the old switch apart to see what caused it to fail. Thank you!

 

I installed the new switch today, and the brakes lights appear to be functioning normally again. Thank you! An ohm meter shows the "B" side contacts of the old switch are all shorted together.

Unfortunately the rear spoiler deployed while I was testing the new brake switch. I suspect the battery had been drained with the constant load from the brake lamps. The battery tested weak, so I will try charging it and replace it if necessary.

I will button everything back up and more fully test, as soon as I can find out where this stray spring on the bottom of my lower dash panel came from.

Thank you everyone for your help.

 

Hi there, I am about to change the stop light switch due to my Auto being locked in park. Have you any tips on the best way of "getting at" the switch?

 

 

Son of a PUP! Being a "manual transmission" guy, I'd never realized this: The 2005 SRT/Limited and 2007 Service manual diagrams are WORTHLESS when it comes to the brake pedal switch wiring.

The diagram in those manuals looks NOTHING like what we see above. I've been here since 2009 and just now found, yet another, BLATANT error in the documentation on our cars.

Ggeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeezzzzzzzzzzzzz zzzzzzzzzzzzzzzzzzz

 

Pizzaguy: So are you saying the above wiring diagram found under the Anti-Lock Brake Section is worthless?

 

I guess... Until he replies there is no way to know what is up.


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NO NO NO! The one James posted and I quoted (from the 2004 manual) appears to be the RIGHT ONE!
The one in the 2005 and 2007 manuals appears to be worthless.

It is 107F here today, if it would just COOL THE HELL DOWN, I'd take my (manual) car apart and verify what manuals have for brake pedal switches. The Auto is apparently wired as per the diagram James posted and I quoted.

If someone volunteers to yank the dash down on their Manual car and document exactly what they have, go for it. Otherwise, I will do so when it cools off this fall.

I added my "Pizza Notes" for my own use:

 

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