Turn signal but no brake

[PCarnathan]

We have a 2009 Mandalay 43A on a Freightliner chassis. The left turn signals work just fine, but no the brake lights. Speaking bulb-wise, they're the same filament so it's not a bulb issue. The right turn signals and brake lights work, too. Looking at the fuse panel there's no separate fuse for left versus right brake lights. If I activate the hazard flashers both sides flash normally. All the running lights are functioning. Just... No left brake lights. Any thoughts?

Pat in Menifee, CA
www.patcarnathan.com

[PCarnathan]

We replaced the turn signal switch yesterday and all is well. A couple of you called it correctly, and for that I thank you. All the bulbs and fuses were fine, but the turn signal switch had failed. The part was about $180 shipped to my door - Freightliner has wonderful customer service!

My thanks to all of you who offered advice and suggestions.

Pat in Menifee, CA
www.patcarnathan.com

[afrescopXx]

You talk about the bulb but have not said you tried to replace. Have you tried a new bulb too?

[wa8yxm]

There may be a different fuse for the brake lights and turn signals, but not for right and left.

If the right brake light and turn signal work
And the left turn signal works but NOT the brake light
Then the problem is the turn signal switch.

[Executive45]

Thanks for the update....Dennis

[11178adm]

the brake lights do go through the t/s switch this allows the t/s to blink when the brakes are applied

[PCarnathan]

Not yet. The turn signal switch at the steering column is broken. I have to hold it down when signaling left. I've ordered the replacement part from Freightliner.

On a two-filament system the brake filament and and the turn signal filament are one and the same, so this is perplexing. Could the power to the left brake light route through the turn signal switch? Without a schematic I can't tell. Bottom line is: The turn signal switch has to be replaced no matter what. In a perfect world the brake light problem will be fixed. In my world... Probably not!

As I learn more I'll certainly share with the forum.

Pat in Menifee, CA
www.patcarnathan.com

[Executive45]

Wonder if the OP found out what was wrong...:h:h:h....Dennis

[fcooper]

Call the Freightliner help desk 1 800 FTL-HELP. It's a free service. Have the last 6 digits of your vin number available.

They will look up the wiring diagram for your specific coach, and can give you advice on where to look for the problem.

I think IVYLOG has the best theory so far.

Fred

[Executive45]

You're assuming the brake light and turn signal use the same WIRE to activate the lamp. They are not. Remove the SOCKET and using a meter, check for power on the turn signal wire, then on the brake signal wire. If one does not work, then your issue is in the wiring. If they both work, then change out the bulb and/or socket. If it's in the wiring, start at the brake pedal and work backwards until you find the problem. You'll only have one fuse for the brake system wiring...Dennis

[Ivylog]

Assuming you are correct about the same filament for brake and turn and it works with the four way flashers, it's in the blinker switch on the steering column. Hopefully you will not have to pull the steering wheel.

*If in doubt about this, try wiggling the blinker switch with the brakes on and someone watching... this may make it work some of the time. You may even be able to bend the contact back into place without replacing. Air brakes does not change what's a fairly simple electrical system.

[JackMS]

I would go with Dave's suggestion. 2 brake switches maybe. That would be a good setup as if one switch goes bad you still have at least one brake light. Could be near the brake pedal either inside or out. Or possibly if you have an electrical control center outside under drivers seat. Good luck

[allbrandauto]

turn 4 way flasher on see if it works probably a turn signal switch problem

[YC_1]

It sounds like you have the wrong bulb or a broken one. Easy to test with a cheap 12 volt tester. One that lights up when it makes connection.Just ground the clip and poke the base of the bulb socket after you remove the bulb.

Take the bulb out and compare it with the one that works. Look for two contacts on the base. Some systems use a seperate bulb for the brakes and some use a dual filament bulb. A dual filament is very common.

[dakdave]

if air brakes there is a switch in system for lites.Usually round with 2 wires mine was right by the treadle valve.mine had two of them.