97 expedition all lights are working except left brake light. checked the bulb and brake switch both are good. im a relative novice, any ideas? thanks

 

Have you replaced the left brake lamp bulb?

 

No its works fine, what I found was I only have 5 volts comir ng to the brake lightnot 12v

 

You are saing the tail lights work, turn signal work for the left side and the hazard lights work? So what you are saying is only the brake light doesn't work on the left side correct. If, the turn signal works then there is something causing it because the turn signal and brake use the same filament in the bulb. The tail lights use the other filament. I wonder if your multi function switch(turn signal) is bad. I am not sure, but I believe the brake light circuit runs through it.

 

Yeah thats exactly whats going on, seems the actual brake light circuit doesn't get enough power to turn the light on. Where is the multi switch located and is it ready to replace or should I just have a mechanic do it. Thanks again

 

Make certain you distinguish between the tail lamps (running lights) and the stop/turn lamps.


In that case, assuming you measured the circuit voltage relative to ground when the bulb was in circuit, indicates an excessive resistance in the feed to the left stop lamp. However, since you indicate that the left turn signal operates normally, I'd conclude that your problem is internal to the MFS.

 

Multi-Function switch is in the steering column. Turn signals and wipers run off this. Most of the time it is a fairly simple job. Remove the trim around the column and has a few smaller bolts holding it to the column. Unplug wire harness and replace it. If you are unsure, have a shop or someone help you do it.

 

You wonder correctly. It's either the multifunction switch, or the connector to it isn't plugged in tight.