Baloo

Title is a little over simplification, but here is what is happening.

One day my turn signals started running slower then, before I had a chance to check them went totally out. I replaced the flasher unit and they worked for a little bit, then the left went out. I replaced it again with the same results.

Yesterday I noticed that the left works as long as I do not use the brakes. In addition, if I am running cruise control, the engine has a very noticeable hesitation if I use the left signal to change lanes and turns off the cruise control although light on dash shows it as stil active and I can hit the set button to reactivate.

Obviously it is something other than the flasher unit. Anyone have any ideas?

Ron Helmuth

a bad bulb can actually affect your cruise control, although typically it would just fail to work at all. The on and off effect has me a bit stumped but here is my take on what is going on for you.

Pull your tail-light bulb-I would go for the left one first-it's a dual filament and it is my guess one of the two filaments is out or grounding out against the other filament. Don't just eyeball it-swap it with the right one for example and see if your results vary. Have at least one good bulb on hand to help narrow it down further. Get a buddy to observe the back end or use a mirror or store window to be sure when you hit the brakes that both stop lights illuminate. Do it at night to be sure that your dash lights and or parking lights are not coming on when you hit the brakes.

If those bulbs all test out well then my next suspect is a faulty tail-light converter box-I don't know the Tacomas personally but on a Runner they are tucked in the rear cargo area. You have a tow package with a 4 pin connector out back near the hitch I am presuming?

give us some more details and we'll talk this out with you.

gdutch

Search button! I went on a road trip last week and noticed that using my turn signals or hazards would cancel my cruise setting. I could still resume at the previous speed, but it was the same effect as tapping the brakes. I know I have at least one tail light out but I haven't investigated yet. I will be checking all my lights this afternoon and replacing the ones that are out, then report my results here.

On a possibly related note, my grounding strap from the negative battery terminal to the body has been broken for some time and I haven't fixed it yet, could this be related?

tunnelmotor99

I agree, if you have a bad bulb somewhere it will cause all sorts of weird things to happen. I had similar issue on my GMC Sonoma one time and when I applied the brakes all the turn signal lights would come on steady and the headlights would go out. The turn signals made the headlights and the dash lights flash too, it all just happened when I was driving home from work one night. After a little investigating I found the right tail/brake bulb was the culprit.

gdutch

Yes, turns out both of my brake lights have the high filament burned out. They come on when my headlights are on, but don't light up when I apply the brakes. I will replace them tonight and see if that fixes it.

gdutch

After replacing both brake lights, my problem disappeared.

Bigdub08

I have had this same problem and to replace the dash assembly

Bigdub08

Was about 450 from dealer