Need help with brake light and turn signal electrical problem

[JC123]

this is a 2000 sahara.
I replaced the rear turn signal bulb the other day and am now noticing other weirdness:

when the lights are on:
1. the brake lights are always on unless I open the rear swing gate, then the third brake light turns off
2. the brake lights turn off when the right turn signal is engaged.
3. the right turn signal comes on but doesn't blink (a steady light on the dash and at the front and rear turn signals)
4. the left turn signal works fine

when the lights are off:
1. the brake lights are off
2. the left signal works fine
3. the right turn signal makes both left and right bulbs blink and the lights on the dash dim/brighten with each click of the signal
4. if I depress the brake pedal, the right signal works as expected but the odometer dims and the speedo and tach brighten. the left signal works normal.

I replaced three fuses related to the rear lights but saw no change.

would appreciate any advice the group has.

thank you,
Jerry

 

[Jerry Bransford]

If you get the new bulb installed backwards it can cause strange problems. Make sure the low and high pins on the bulb are in their correct slots.

 

[JC123]

thank you Jerry.

I didn't realize there was a "wrong" way to install the bulb and for a moment thought you might be having fun with me (similar to suggesting that the drummer might have the sticks in the wrong hand) but gave it a try anyway. The only pins I see are on each side of the metal base that hold the bulb into the housing. there is a single bump/protrusion/contact on the bottom of the bulb. I rotated each bulb in the passenger-side tail-light assembly but with no change.

I'll keep researching and report back. in the meantime, I'm open to other ideas.

Happy New Year.

 

[machoheadgames]

I’m going to guess bad multifunction switch in the steering column. It cuts off the brake lights when the turn signals are on in order to blink the brake light as a turn signal. When you start getting funky behavior between the rear turn signals and brake lights, 9 times out of 10 it’s the MFS screwing up. Could be a wiring issue or something else but….

 

[TJ4Jim]

thank you Jerry.

I didn't realize there was a "wrong" way to install the bulb and for a moment thought you might be having fun with me (similar to suggesting that the drummer might have the sticks in the wrong hand) but gave it a try anyway. The only pins I see are on each side of the metal base that hold the bulb into the housing. there is a single bump/protrusion/contact on the bottom of the bulb. I rotated each bulb in the passenger-side tail-light assembly but with no change.

I'll keep researching and report back. in the meantime, I'm open to other ideas.

Happy New Year.

Something not making sense, you stated that the rear turn signal bulb was replaced then you said there is only one bump on the bottom. That's telling me it's the wrong bulb as the correct bulb should have dual filaments.

 

[machoheadgames]

Something not making sense, you stated that the rear turn signal bulb was replaced then you said there is only one bump on the bottom. That's telling me it's the wrong bulb as the correct bulb should have dual filaments.

I missed that. That’s definitely a problem.

 

[JC123]

Something not making sense, you stated that the rear turn signal bulb was replaced then you said there is only one bump on the bottom. That's telling me it's the wrong bulb as the correct bulb should have dual filaments.

I think you be onto something.

I installed bulb type 1156 because that's what I had on hand and it seemed to fit but I checked the owner's manual and see that is for the back-up light. Bulb type 1157 is indicated for the stop/tail/turn lamps. I'll get one of those and if that doesn't do it, will investigate the multifunction switch that @machoheadgames suggested.

thanks all

 

[machoheadgames]

I think you be onto something.

I installed bulb type 1156 because that's what I had on hand and it seemed to fit but I checked the owner's manual and see that is for the back-up light. Bulb type 1157 is indicated for the stop/tail/turn lamps. I'll get one of those and if that doesn't do it, will investigate the multifunction switch that @machoheadgames suggested.

thanks all

Yeah an 1156 in the brake spot will absolutely be problematic. It is probably bridging the gap between the two factory prongs in the tail lamp and backfeeding each other. I bet everything goes away when you put in an 1157. 1157 is dual filament and 1156 is single (bright) filament.

 

[TJ4Jim]

I think you be onto something.

I installed bulb type 1156 because that's what I had on hand and it seemed to fit but I checked the owner's manual and see that is for the back-up light. Bulb type 1157 is indicated for the stop/tail/turn lamps. I'll get one of those and if that doesn't do it, will investigate the multifunction switch that @machoheadgames suggested.

thanks all

Yep the 1156 is definitely not correct.

 

[JC123]

y'all were right: user error. swapping in the 1157 fixed it.

thanks again.