1996 F250. Had this truck since new, Do all my own work (retired diesel mechanic). Anyway, took out the flasher relay and jumped the spade holes. Left and right dash lights are on solid as well as exterior signal. Went to autozone and the relay listed has the same number but was 1/2" longer. Did not work. Returned it. So with it jumped and apparent power I'm stumped. Any ideas?

 

Are you buying a "heavy duty" or a electronic flasher? The original flasher works on heat. This heat is generated by bulb load. If you have LED bulbs or the wrong bulbs in the exterior lighting, they can draw less current and that is not enough to heat the flasher and make it work. But a heavy duty flasher does not work on the bulb load to flash, so it will ignore bulb load. People usually use these for trailer towing where the trailer is hooked to the taillights. I am sure you have seen trucks when a trailer is hooked up the flasher flashes very fast. This is because of the increased bulb load from the added trailer lights.

P.S. I just was thinking, if you do not have enough bulb load to heat the flasher, then your bulbs will usually stay on solid. You said the bulbs were dark with the flasher plugged in. But if they are lit during your jumper test, that means the new flasher has to be faulty or the wrong part.

 

I have an F350 7.3 diesel, same year, and I'm also having blinker problems for 3+ weeks now.
Long story short... whatever parts they gave me at the local store (3 of them) is not the right part for the turn signals. And stupid me, I thought it was the original turn signal flasher that was bad and threw it out (turned out it was a burnt bulb after all).

I don't remember this truck ever having a lights problem when towing a trailer. Brake lights work, just for reference.

The existing hazard flasher is a short aluminum-bodied cylinder, embossed with "Wagner" and "552 12v" on the end, and stamped "Motorcraft" and "D2AB-13350-AA" around the side. I assume it is a "heavy duty" version. It still works. And it looked quite the same in shape/size as the one for the Turn Signal (but alas, I didn't write down any markings it had before I tossed it!)
The replacement turn signal flashers do not work properly at all. I've got 3: Two Novita 552 and 1 Novita "Long Life" 552.

After replacing all the bulbs and numerous flasher swaps between sockets... the original "Wagner" works for the Hazards.
If I put it in the Turn Signal socket-- then the turn signals work-- BUT, the light takes 5 or so seconds to the first flash, and the flashes are slower than they should be. (This echoes what Franklin2 said about heat activating those flashers.)

The new 552 flashers DO NOT FIT properly on the back side in the hazard socket-- they are too long. We got one in with some serious tweaking--- but the truck frame is right behind there and there is no clearance. Those Novita 552's are maybe 1/8" longer than the Wagner. (And they are longer than the original turn flasher also as I compared them before I tossed it). The 552 Long Life is almost an inch longer than the original, and didn't work *at all* (no turn lights). Even if it did, I wouldn't be able to put the fuse panel cover back on. Not possible to get it into the hazard socket, even to test.

The Novita 552s come on and "flutter" super fast, then settle into a fast-blink pattern that's not right. And the more you use them the longer the fluttering is. Presently, one of them doesn't get to the blink part at all. The one we tried (me and the body shop guys) in the Hazard socket made the hazards flutter irregularly.
The fluttering is so fast that an observer can't be sure the signals are flashing at all.

For now, I put the working hazard flasher (Wagner) in the turn signal socket... and I'm without Hazard Lights. (As per the wiring diagram it appears to be either/or). Hopefully I won't need them. So far, its been "working", even if blinking a bit slow, for about 4 days. Fingers crossed.
(Actually the Novitas DID work for 1 day, and failed after that.)

Soooo, the local parts store (CarQuest) and online shops like O'Reilly and Autozone all show the same flasher part# for this truck. Either that info is wrong or these Novita brand flashers are just bad. Or something.

The only alternatives I see online (or in-store) are the square-plastic-box ones, and I cannot be sure any of those are correct...and they all look longer than what will fit under that fuse panel cover.

The good news is that the old "Wagner 552" flashers are all over the internet, so I plan to get a few for when this lone hazard flasher fails.

If anyone can point me in the right direction to the proper flasher, it would be SO appreciated. I'll be traveling a little over the next few days and will be able to check several different parts stores for alternate brands also.

I don't know if this helps you, Uchytil, but if so, you're welcome to it!

--CW

ps. sorry so wordy--I'm just out of options and hoping someone else knows

 

I looked a little bit, I see the ones you bought and I also see the square ones. If you want to experiment and try to make some of them fit, why not get some male spade crimps, short wires and then two female spade connectors. The flasher would not fit under the fuse box cover, but you could remotely mount it instead. Might be louder also.

If you use the tow wiring from the factory(if your truck has it) for the trailer lights instead of tying into the trucks rear lighting, then you will not have the fast flasher problem with the regular flasher unit. The regular flasher unit is handy, if you do lose a bulb on the truck it will not work correctly and alert you that you have a problem(as you have already found out). Using the heavy duty flasher you lose this feature.

 

Thank you Dave for the suggestion. Just need to get to a parts store. Today where I went, they no longer had an auto parts store. Dang.

Hopefully I'll be able to find something to try with this on Monday. This truck's hood is coming apart and a new hood will be installed then. The current hood is not original... it was a replacement for some hail damage some years back.
Meanwhile, trying not to go anywhere I don't have to because passing semis are a terror if the wind is wrong.

--CW

 

We're back in business on the turn signals! Yay.

Went to NAPA, and bought one of their NAPA-brand 552 flashers.
It is the same length as the Motorcraft, a little different shape on the cylinder.
So far it works, although I'm watching it like a hawk. It got through multiple starts yesterday, and lots of use in town, and the blink rate is a tad faster than with the Motorcraft flasher.

The NAPA packaging says "Direct Replacement for 536 or 552".
I am still going to try to get some of the original Motorcrafts online somewhere, to stash them.

Of note, when I google "Flasher 536", and check some links... the auto stores say the 536 doesn't fit my vehicle... BUT, now I see a variety of short flashers in various brands labelled "536/532" and also "32CP" printed on them. And a little info springing up about some of them being for LED or LED+regular bulbs.

This has taken me nearly a month to sort out. Maybe the info will be helpful to someone else.