wiring for a 03 winnebago sightseer on a 02 workhorse

[BingMyDog]

When turning on the left turn signal, the lights on the instrument panel flash, the four turn signals, and all the side markers.
Don't now if this is a winnebago or a workhorse problem.
I think it is a ground, but don't know where all the grounds are located.
All suggestions are welcome. I will try anything.

Thank You

[TNGW1500SE]

Replace the bulbs first and if there's still a problem, add a new ground instead of looking all over the place for the old one. You can't ground it to much.

[allbrandauto]

before going thru all that work pull the rear turn signal bulb on that side and see if dash lights stop blinking if yes your problem is there if no pull the front bulb and see I have seen the two filaments in the bulb touch each other giving this problem

[olfarmer]

I agree, it sounds like a bad ground but I can't tell you where to look for it. Bad ground connections do things like you described. I would try the Winnebago site. Good luck!

[1995brave]

Go to the Winnebago site and download the wiring diagrams.
https://winnebagoind.com/product-resources/product-information