A funny thing happened on the wat to work yesterday morning. (Back story- 2 weeks ago I converted to a 4 light rear brake light) While sitting at a stoplight with my left turn signal on and my foot on the brake, the turn signal starts hyper-flashing. This happened for 8 blinks then returned to normal. As I drove throughout the rest of the day, I use my car for my job, this did not happen again. I'm not looking for answers, as I will be searching for loose wires this weekend, but thought it quite strange. AND, my HCMBL quit working. Oh the joy.

 

Yeah. Look for the loose connection in your work.
Remember the old days, old cars. One non working bulb would cause the other to flash faster.

 

Does HCMBL mean CHMSL(CenterHighMountedStopLight), if so that is probably the prob.

 

Dig in and find the problem, and give us an update when you resolve the hyper flash.

Did you solder the connections? Or crimp connections

 

I found the break. It was where the wire goes into the resisitor that I installed for the led's.
Now comes the brain teaser.
I cut the wire to replace the resistor and the lights started working normally. I had the emergency lights on at the time, the hyper blinking stopped and the brake lights work.
So now there is only one resistor on the passenger side and all appears well.
Once again this little trucklet defies what I know as common sense BUT it is working so I will be satisfied and accept that.

 

Do the bulbs have built in resistors?

 

Nah. I think that by having the emergency blinkers on I 'fooled' the computer so that when I turned the car off the system reset.