Rears keep flashing at a rapid rate, but front only flash once.

 

When did this behavior begin? What changed?

Usually such behavior may be seen when one of the bulbs is burned out or one of the filaments in a double filament bulb is burned out. At least for the rapid flashing. Don't know about the single flash.

Such mysteries are often the result of losing a ground on one of the lighting circuits. Can be where it connects to the frame or in one of the bulb sockets (corrosion)

Check the sockets and trace the ground wires to the splice packs and then to the frame


Attach a full featured scanner that can read body control module codes and you may find your answer. If it's not under the hood, chances are it is controlled by the BCM.

 

just bought it. Definitely not filaments.

 

Scanner showed no problems

 

P B C X capable scanner that supports GM enhanced diagnostics/manufacturer's codes?

Wired or bluetooth (just wondering)? I have an OBD MX+ that I use with the OBDlink sw which now includes free enhanced diagnostic modules for GM, Ford, and I am not sure what else. Also use it with a program called car diagnostic pro, like $10 paid. Very granular scanning if you wish. And I'm getting to love FORScan Lite. Use a service function once and it has more than paid for itself.

Sorry bit of a tangent.

Does the vehicle use the same bulb for turn signal as it does for brakes? Are you possibly lighting both filaments at once on one side in the back if they are up against each other which of course they should not be?

What happens if you pull each of the offending bulbs one at a time?

If it is a flasher module (solid state "relay" so to speak) just swap it out. I am not a parts shotgunner nor do I recommend it but if you have checked out the grounds, and it is not internal to the BCM, and removing a bulbs does nothing, and swapping them both with fresh bows does nothing, that would be my first guess

 

got to finish MG before I have time to troubleshoot

[QUOTEthe front and rear bulbs flash once with the flasher clicking at its normal rate, the the front bulbs stop flashing and the rears contine, but at double their normal rate. Never seen anything like it and won’t have time to troubleshoot it until I finish my MG.




=derf;66262]P B C X capable scanner that supports GM enhanced diagnostics/manufacturer's codes?

Wired or bluetooth (just wondering)? I have an OBD MX+ that I use with the OBDlink sw which now includes free enhanced diagnostic modules for GM, Ford, and I am not sure what else. Also use it with a program called car diagnostic pro, like $10 paid. Very granular scanning if you wish. And I'm getting to love FORScan Lite. Use a service function once and it has more than paid for itself.

Sorry bit of a tangent.

Does the vehicle use the same bulb for turn signal as it does for brakes? Are you possibly lighting both filaments at once on one side in the back if they are up against each other which of course they should not be?

What happens if you pull each of the offending bulbs one at a time?

If it is a flasher module (solid state "relay" so to speak) just swap it out. I am not a parts shotgunner nor do I recommend it but if you have checked out the grounds, and it is not internal to the BCM, and removing a bulbs does nothing, and swapping them both with fresh bows does nothing, that would be my first guess[/QUOTE]

 

Simplest thing to do is check the numbers on the bulbs and make sure they're the correct ones. If so, I'd look for a loose ground wire on the front ones. Love the MG. What year? Late 50's?

 

Try the hazard lights and see how the bulbs behave. On my L series all direction lighting runs through the hazard switch. Sometimes I have to sweep the switch a few times to get everything back in order.

 

54 tf

 

Same with hAZARAD LIGHTS. FRONTS BLINK ONCE THEN QUIT, FOLLOWED BY REARS BLINKING AT DOUBLE RATE.