When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
2001 f350 I have had this truck for years never much issues always maintained and all service done by me. Well yesterday when turning my blinker on the hazard light came on I am stumped as to what could be next. If the blinkers are turned on the front flash as the hazard where turned on but back flash with signal direction Right turn signals = back right flashes but both front flash. What I have done are the basic normal fixes and checks New flasher installed ya that's not a fun one to get to !! Maybe something I am missing? Now I put a multifunction switch and still same issue??? Thanks
Lights do weird things when they have grounding issues.
I haven't heard that particular one, but since you've already replaced the flasher and multifunction switch I'd try removing one of the front bulbs and testing it.
If the other side blinks normally reinstall the bulb and remove the other side and retest.
If one side doesn't work on either above scenarios check for ground from the bulb socket.
I just looked over the schematic, the only thing I can see that might cause that is the LtGrn/white wire (left front signal) and the Wht/LtBlu wire (right front signal) wires being shorted together, or a failure inside the multifunction switch.
I'd pull the multifunction switch plug and apply power directly to the above mentioned light wires (pin 3 and 2) and see what lights up.
I had really strange blinking conditions when installing LEDs in the ole 66. Ended up having to install resistors to ground. What it was doing made no sense logically to me. Based on the schematic it shouldn’t of had power to blink when it was.
You might try changing bulbs first. May be some issue with them or the sockets. Just pulling and replacing could fix a potential connection issue. It’s cheap to try anyhow.
edit: I also meant to second checking the grounds. Since kwik posted about it I’ll make it a 3rd.
Lights do weird things when they have grounding issues.
I haven't heard that particular one, but since you've already replaced the flasher and multifunction switch I'd try removing one of the front bulbs and testing it.
If the other side blinks normally reinstall the bulb and remove the other side and retest.
If one side doesn't work on either above scenarios check for ground from the bulb socket.
Welcome to the site!
Another vote for making sure all the grounds are clean, bare metal, corrosion free. Electricity will find a path to complete the circuit, even if it is through another circuit that has a better ground. Much like water. If there's a path for a leak, it will find it.
But bad grounds can cause some weird things in a 12v system. Had a 92 Chevy once that only 1 rear brake light would work unless you hooked up an extra body ground. The factory 1 was still there and clean, but no bueno unless a second was tied in. Never did figure that one out.