i have a 98 F150 and having blinker issues.. I know when its blinking rapidly it means there is a light out but when i turn my drectional on before the click, meaning before it stays on without needing to hold it, the directional works fine. Now there are times where i would turn it all the way on and it would work then the next time i go to use it, it would blink fast again. it has to be a loose connection or something since the light works at times and other times it doesnt. Any ideas? Thanks.

 

Do you have tilt steering?

Using a ohmmeter, check both bulbs, front and back. If it isnt that, then it is one of the contacts in your turn stalk. you have to remove the steering wheel neck to get to it

 

No, it isnt tilt steering

 

It could also be the multifunction switch (basically the whole turn signal lever and switch assembly). I recall having similar issues before I replaced mine. It's been a few years so I don't remember exactly the problem, but I recall it had to do with the turn signals not always working (rapid blinking on the dash, but the turn signal not working). Was worse in subfreezing temps.
A bonus for me was that replacing it also fixed an occasional problem I had been having forever with my windshield washer (sometimes worked, sometimes didn't), but the new one also introduced a new problem where occasionally (not always) if I turned on my left turn signal while in cruise control, it would turn off the cruise. Now you know why they call it a multi-function switch - it has the capability of screwing up all sorts of things.

 

its funny you say that about the windshield washer not working because i have the same issue. It works when it feels like. Seems like everytime in the winter when i needed it, it wouldnt work.. just my luck haha. but ill look into that multifunction switch. It could very well be that. and i dont have cruise control so hopefully that is one less function it can screw up. thanks for the info