tightlinez

My passenger side rear brake light keeps going out the second I press the breaks…

I tried using GE Standard 7443/BP2 12v. and burnt two already. (Only the brake filament goes out instantly)

Lexus bulb had 7443 and some other numbers.. so i'm assuming it's the 7443.

I hope this in not a serious electrical issue..


Any help is much appreciated.

salimshah

Although bulbs (as long as they are for 12v and fit the socket) are totally interchangeable [intensity of light is a different issue and depends upon wattage and efficiency], for brakes light I recommend OEM. [There is a current sensing bridge that determines bulbs are functioning and that requires the bulbs to be of certain current drain (+/-)]

Bulbs popping too soon or instantaneously is a different problem. The bulbs pop either due to age, or stronger than expected current draw.

Stronger than expected draw happens when there is excessive voltage (more than the rated 12v) ... very unlikely unless you have modified electrical system (another battery)

OR ... a more likely scenario ..

The contacts are loose causing current spikes.
The bulbs have low resistance when they are off (cold). When you complete the circuit, there is an instantaneous surge which ramps down quickly as the filament starts glowing. When you have a loose contact then the current fluctuates and the surge happens again and again causing the bulb to pop.

Finding the loose connection is hard unless you see corrosion. Look at the socket. If you notice corrosion, I would suggest replacing the socket, as the protective layer has been compromised. Also make sure the wires on the bulb are in the middle of the spade. If the connection at the bulb/socket is ok and the socket checks out , then trace the wire to connectors.

The source could be a bad brake switch. If only one location fails, then there is more likelihood of a problem in that particular branch. Usually Lexus connectors are good so I would start
a) bulb wires.
b) Socket
c) Brake switch.

Finally do post, how the problem was fixed.

Salim

bob2200

I found a listing for:

"7443B2
24.98/5.4 Watt, 13.5/13.5 Volt, 1.85/0.40 Amp T-6 1/2 Automotive Bulb"

at bulbs.com. Perhaps there is a difference between a 12.0v 7443 and a 13.5v 7443B2? The easiest thing to try first is to try a bulb that specifically states it operates on 13.5v (instead of 12v).

acthad

Hi,
I see a boat trailer in your signature. Make sure to double check the brake controller connections to the trailering harness. You might have a short somewhere.

tightlinez

Thanks for the good info and fast responses. I’m going to do some testing today and hopefully I just got the wrong bulbs.

I’ll let you know what happens..

Thanks again!

tightlinez

**update**

I carefully examined the socket and it looked fine…But when I checked the tow hitch harness and it was completely corroded with some green and white scum..

I cleaned the contacts with some low grade sandpaper and terminal grease and now everything works perfect! No more brake light sensor on the dash.

I’m always fishing in brackish water so the mild salt water may have gotten on the contacts when i launch my boat.

Thanks again all!

salimshah

Great!

Now the bad part .. once you clean and sandpaper, the rust will come back [law of nature]. You can apply a thin layer of grease and keep the elements away from the metal.

One more thing, you like to wash the underbody every time you get it wet and follow that with a spray of wd40.

Salim