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Andy
Andy, Truck Diagnostic Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1675
Experience:  International and Isuzu trucks , International, Maxxforce, Cummins and Isuzu engines, Diagnostic and electrical troubleshooting specialist , Hvac and truck /trailer refrigeration troubleshooter
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Right side brake light does not work turn signal does, 2005

Customer Question

right side brake light does not work turn signal does
JA: What's the make/model/year of your truck? Engine type?
Customer: 2005 cxn mack mack 355-380 engine
JA: Are you fixing your truck yourself? What have you tried so far?
Customer: yes ,I replaced turn signal switch ,right tail light ,abs brake controller
JA: Anything else you want the truck mechanic to know before I connect you?
Customer: I ran a new wire to the right side tail light
Submitted: 3 months ago.
Category: Medium and Heavy Trucks
Customer: replied 3 months ago.
the left brake light works
Customer: replied 3 months ago.
when the right brake light quit the cruise also stopped working I believe what ever shorted the brake light is also the reason the cruise don't work or maybe just the oppisit
Expert:  Daniel Wilson replied 3 months ago.

Hi my name is***** will be glad to try to help. Give me some time to check on some diagrams on this

Customer: replied 3 months ago.
ok I'll wait to here I have asked other about this problem they tell me it's the signal switch but it works fine in another truck
Expert:  Daniel Wilson replied 3 months ago.

Thanks for the update. And the one from the other truck still is the same I gather. If brake light signal is coming out of the switch it has to be an open circuit or ground issue/possible poor connection at the tail light itself or bulb. Test and follow power in the rear harness for the stop lamps. Let me know

Customer: replied 3 months ago.
the blub was replaced for that reason even though the right signal worked there is a new wire going from the junction block to the right brake light the power at the junction is correct for two reasons 1 all lights work on the trailer correctly , 2 the power on the junction block matches the same as the other truck same make, model, year
Customer: replied 3 months ago.
I can make the brake light work with a jumper wire If the ground is bad seems odd it works with a jumper wire
Customer: replied 3 months ago.
is it possible that the cruise is shorting the brake light or the other way around they must be connected some where but where?
Expert:  Daniel Wilson replied 3 months ago.

Try the turn signal on the other side to make sure it doesnt interfere.

Customer: replied 3 months ago.
left side works on tractor and trailer right brake light works on trailer but not tractor
Expert:  Daniel Wilson replied 3 months ago.

Is there any power in the wiring harness coming out of the switch and back to the right brake? Sounds like an open circuit to me.

Customer: replied 3 months ago.
the power coming out of the cab to the junction block on the fire wall must be ok or the trailer lights wouldn't work and by putting a jumper wire to the right brake light on the truck it works , with the wire for the right brake light disconnected at the junction block there is power there
Customer: replied 3 months ago.
is there anyway possible the cruise is the problem? (or the throttle)
Customer: replied 3 months ago.
the right signal works the brake and signal use the same wire
Expert:  Andy replied 3 months ago.

Hi there . My name is Andy! Would a diagram help you here ?

Customer: replied 2 months ago.
not sure it might if it would show the connection between the brakes and the cruise (or the throttle)
Expert:  Andy replied 2 months ago.

It should not be related to the cruise at all .

Expert:  Andy replied 2 months ago.

Do you still need help ?

Expert:  Andy replied 2 months ago.

Looking for an update on this . Do you still need assistance ?

Customer: replied 2 months ago.
no thanks I am wiring the brake lights to match the trailer lights since the trailer plug works correct
Expert:  Andy replied 2 months ago.

Oh ok . That works I guess .