Hi,
I searched for my issue and reviewed the video "1999 Ford Ranger - Diagnose and Repair TurnSignal Failure". But, no luck yet in resolving my turn signal issue. This is a 1999 Ranger XLT 3.0 5 speed manual 2 wheel drive truck with about 226,000 miles on it.

What re my next steps to getting the passenger side rear turn signal to flash properly?

This issue started with a burned out drivers side brake light, intermittent turn signals, and only one instrument panel dash light. After getting a warning b a local police officer for the burned out brake light, I did the following:
1) replaced all passenger and driver side rear bulbs: 3156s and 3157s bulbs
2) replaced the under-dash relay, Multi-Purpose Relay TRQ ELA13292, purchased on-line from 1A Auto
3) replaced all instrument panel dash lights with #94 bulbs
4) replaced all instrument panel warning lights with #74 bulbs
5) removed, sanded, and reinstalled four ground screws in engine compartment: 1) driver side inner fender, middle of fender, near the relay box; 2) radiator support in front of and next to battery; 3) on firewall on wiper screw, ground strap going to driver side exhaust manifold, and passenger fender, middle of fender. I sanded all paint and oxidation off fenders, screws, and electrical connections
6) checked ground with an ohm meter: removed battery to have easier access to ground screw in front of & near battery on radiator support: touched one ohm meter lead to negative cable and other lead to all four ground screws before and after cleaning the ground screws. The ohm meter read 0.5 both before and after sanding on all four screws.

Doing all of the above six actions made an improvement as the dash lights do nto come on intermittently anymore, and I now have a driver side rear brake light - even a new bulb would not light before replacing the relay

The issue is the right rear blinker/turn signal amber light turns flashes but both rear brake lights also flash, like the flashers are on. Only the right front amber & right turn signal dash lights flash

Which of the following is my next step? The headlights and front amber turn signals/flashers/running lamps all work properly.
1) Replace the multi-function turn signal switch: $38 online with 1A Auto, about $85 at O;Reilly's Auto Parts
2) Replace the #11 engine bay 15A relay: Parklamps Relay and Main Light Switch: #F57B-14B192-AA
3) Replace the #12 engine bay 30A relay: Main Light Switch and Multifunction Switch
4) Locate other grounds and clean them - if this is the next step, where are the other grounds?

Also, I just found online this relay but where is it located? 1999 Ford Ranger Hazard Warning Flasher Multi-Purpose Relay TRQ ELA13289

TIA

 

Well, I replaced the multi-function switch and no change. Turn the right blinker on and both rear lights flash.

Anyone have an idea how to fix this?

 

I suspect that you have a ground problem with one of the tail lights. Clean and confirm both tail light grounds and see if things improve. When a light comes on that is on another circuit it usually is because the intended circuit has a bad ground and the current goes looking for a ground it can use.

 

@nelbur I will look for more grounding screws, and I suspect they will be back by the taillights.

I also learned that the flasher relay I removed from the Ranger has 6 pins/terminal. It is part #F67B-13350-AA . The 6th pin/terminal is very small and is not numbered. I found in a post on this forum where a discussion occurred about the 6th pin/terminal. The discussion was confusing because the author of an answer wrote a confusing sentence: "....So there was a separate in or out for turns, the 6th pin...." 6th pin-terminal flasher relay

I also learned that Autozone part #SW1977 and O'Reilly 2TSS11 both say those parts fit my 1999 Ranger. However, those are both 14-terminal multi-function switches but the one I removed from my Ranger is a 16-pin terminal. he O'Reilly 16-pin terminal multi-function switch is part #2TSS16.

The fun continues tomorrow!