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Old 09-11-2021   #11
Matt B
 
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Default Re: 3rd brake light not working. CHMSL

Did you check for proper ground? I don't remember how ground was routed to the sockets but if your lower brake lights work and the switch is new it's likely that current is available at the sockets. So maybe an issue with grounding?
I'd check for both, ground and current at the sockets first and then follow the path that doesn't work.

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Old 09-11-2021   #12
jad1014
 
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Default Re: 3rd brake light not working. CHMSL

I haven?t checked a ground. I did get the FSM recently and will check it for the ground location- thanks

Here is what the wires look like going into the SLS. The light blue wire is for CHMSL if I understand correctly? White goes to the turn/hazard switch assembly if I understand the FSM. What is the orange - a ground? What?s the small blue plug? There is some tape on the three wires going into one of the SLS connectors. I?ll have to take it off and see what I see.



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Old 09-11-2021   #13
Z51JEFF
 
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Default Re: 3rd brake light not working. CHMSL

It's the switch,I've replaced it 3 times in 15 years. One down side to doing the Euro taillight conversion,when the switch goes out you have no brake lights at all.
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Old 09-11-2021   #14
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Default Re: 3rd brake light not working. CHMSL

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Originally Posted by Z51JEFF View Post
It's the switch,I've replaced it 3 times in 15 years. One down side to doing the Euro taillight conversion,when the switch goes out you have no brake lights at all.
I replaced the switch. I was fully expecting a done deal after replacing the switch based on all the good threads I found in search.
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Old 09-12-2021   #15
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Default Re: 3rd brake light not working. CHMSL

Orange is current. That's where your energy comes from. Should attach to the center lug of the three.

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Old 09-12-2021   #16
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Default Re: 3rd brake light not working. CHMSL

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Orange is current. That's where your energy comes from. Should attach to the center lug of the three.

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Old 09-12-2021   #17
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Default Re: 3rd brake light not working. CHMSL

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I MAY be wrong, but going from memory, both switches will cause an in/op third brake light. I vote either bad switch or just as likely, all those expensive little bulbs in the lamp are out.
Please spend the $10's a buy the second brake light switch, one controls bumper lights the other controls the high mount. BOTH need to be working.
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Old 09-12-2021   #18
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Default Re: 3rd brake light not working. CHMSL

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Originally Posted by Corvette95 View Post
Please spend the $10's a buy the second brake light switch, one controls bumper lights the other controls the high mount. BOTH need to be working.
My understanding is there is one brake light switch, two connectors. One connector for the bumper lights, one for CHMSL.



The orange white and blue go into the SLS. The second blue connector with the grey and a black/white wire also goes into the SLS. No?
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Old 09-13-2021   #19
Matt B
 
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Default Re: 3rd brake light not working. CHMSL

Only the triple connector is involved in brake light action. As already stated: the center one feeds energy, two outer ones route it to the brake lights when the switch is engaged.
The other connector to my knowledge disengages the cruise control but I'm not 100% sure.
You may try to bridge the connector with a bridge lead center-left and center-right which should engage your lights. If not there is a broken circuit. Also you can measure resistance between the connector and the bulb socket to check for a broken circuit. Refer to the FSM to find out which wire is yours.
Again: easiest point to start from is to measure at the third brake light sockets. You either lack positive or ground. Find out what's missing and follow the path down to either the body or switch.


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Last edited by Matt B; 09-13-2021 at 02:46 AM.
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Old 09-13-2021   #20
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Default Re: 3rd brake light not working. CHMSL

Anybody working on this keep in mind you cannot unplug the switch and just leave it and get back to it latter. Once the switch is unplugged the lights will stay on,ask me how I know.
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