E21 hazard switch

[Axuise]

oh well im feelin even more dumber now :/ alwell all part f the learning experience. slips are always bound to happen so i expect cuts n gash's haha thats not a problem. hell its happened more times than i can count. use to board so i just laugh when i bleed. alright so i guess ill try n tackle the hazard as described. thanks again guys for the advice and patience with me.

[zohanisback]

It's a fairly simple job, you just have to be very careful when taking the switch apart. There's at least 3-4 guys on the forum that could show you scars from letting their knife or screwdriver slip when prying the switch apart.

Ditto. When I took mine and a couple others apart, I knew if I slipped the tiny flat head I was using was gonna go right through my finger...

[lbottini]

Purchased a replacement from autohausAZ for $20.90. Thanks gsumzzz.

[Tom D]

so as it turned out last week when I took my car out of storage the hazards were flashing and the button wouldn't stay in. this was the first time I have had any problems with the switch in my 34 years of ownership. so right after I wrote the post above I found myself disassembling the switch. a bend of the spring and peg and its working like new again and yes, like brian said, my pocket knife did draw blood.

here's the switch broken down. you can see that each wire has its own internal contact on the case as well as the button.



the button has two sets of contacts. the top one handles the hazard lights and the lower one deals with the turn signals. when the button is pushed in only the lower contact ring makes the connection and when the button is out only the top contact ring makes a connection (except #30 and 49 which are on the lower ring, they also make contact with the button out)



heres the plug.
turn signals
#15- power in from fuse 15
#49- power out to the turn signal relay
#59- power in from the dash light dimmer switch to power the red light in the hazard switch
resistor is soldered to terminal 59 and the red light contact inside the switch.
#31- ground for the red lamp

hazard lights
#30- power in from fuse 17
#49- power out to turn signal relay
#49a- power in from the turn signal relay
#L, R- power out directly to the left and right turn signals bypassing the turn indicator stalk.
#31- ground for the red lamp



that's it guys, sorry if I took all the black magic out of it.

[Shimmy55]

Smells like a fresh batch of faq cookies in here.

[dumbclub]

Great write up Tom!
The photos are excellent.
Definitely FAQ material.

[ekr470]

I just want to know how this is the first time your hazard switch decided to act up.

[Tom D]

^ seems that the older(pre-facelift) switches were different and more robust.

remember that everything i wrote above is for my 1977 model car. for giggles I decided to look at the wire schematic for the facelift cars. dumbclub was right in that there are more appliances on fuse 15 and 17 then there are on the early cars.

fuse 15 not only handles the turn indicators and wipers, but also the horns and power mirrors.

fuse 17 takes care of the hazards and the interior lights just like the pre-facelift cars, but also handles the tach, clock, seatbelt buzzer and lamp.

however the switch itself appears to be have the same terminal numbers and operates in the same manner. also keep in mind that all these appliances are spliced into the same fuse and wired in parallel not wired in series. this way if one component fails everything else on that fuse will continue to function, unless of course the component shorts to ground and blows the fuse.

[Shimmy55]

A note on the repair, both of the late hazard switches I've dissected, not only the arm's were bent but the pin at the top of the arm was loose. The pin is essentially a rivet that's pressed in. The hole oblong's and allows play. I used a pair of needle nosed vice grips to hold on to the arm and tapped the arm with a hammer to secure the pin. If I could get the arm out of the housing, I would micro torch it and put a drop of solder.

early vs late












I've relocated the haz switch in my 82 to the pre facelift location."Conveniently out of the passengers reach". I used the round early top housing and screw on button with the later bottom housing and contact's so that it would match the plug harness. everything works perfectly.

[504Present]

Hey Tom, you seem to be one of the most experts on this particular issue.... just want to get your (or anyone else's) opinion.... When I bought my 82, it had the reliable handy-dandy screw in the switch (I guess the button would not stay in the closed position and they didn't want to mess with it). Anyway, just got a new switch from Bavarian Autosport and removed the old and installed the new. I couldn't believe how easy that actually was. It's been driving me crazy to be without turn signals and was hoping this was the fix. So this is what happened when I installed the new switch. Keep in mind that everything except my hazards and signal lights are working. I plugged the new switch and the button stayed when I pushed it but it kept blowing two of the fuses. I changed the fuses and it kept blowing them. Any advice before I discect my switch? Could it be a faulty switch perhaps or should I just take the car to a shop for them to check the wiring?

[504Present]

So funny I read that some of us were riding out there with the handy-dandy screw in our hazard switch button.... Found that the reason my fuses kept blowing was because I kept plugging in the switch in the "on" position. I tried it with the button pressed in or in the "off" position and voala and to which I also said "Duh"! Works like a dream.

[Fausto87]

There's at least 3-4 guys on the forum that could show you scars from letting their knife or screwdriver slip when prying the switch apart.

So true, I just stabbed myself trying to pry the f*cker open with a knife

[Thecatmilton]

So true, I just stabbed myself trying to pry the f*cker open with a knife

I did that too!!

[Manny G.]

I bought an '81 320is last month with 50k original miles, all original parts... literally a garage kept time capsule When I bought the car, the hazard switch was working, I tested it vigorously lol

Just my luck, a switch that was fine for 35 years SUDDENLY has this problem as soon as I buy the car ... I can't make this stuff up.

[jaredmac11]

I drilled a small hole through the housing and in to the button itself, from the side. Then I put in a small nail, cut to about a fifth of its original size (head in-tact). This allows the button to always be pressed in and functioning. While it removes the ability to use the hazard, it saves me the headache of a switch going bad.

I'd recommend this for anyone.

[papasbmw]

Exactly how do you remove the hazard switch on a 1974 BMW 2002? From the front or from the back?

[bassboy3313]

Exactly how do you remove the hazard switch on a 1974 BMW 2002? From the front or from the back?

Just an fyi, this is the e21 section. Although someone may have the answer for you here, you'd probably get a quicker response in the 2002 section.

[Somjuan]

Here you go

[papasbmw]

Thanks much Somjuan. The redirect was very helpful

[Somjuan]

Glad to help!

[Coffin1967]

Hi,

My car is E21/316 1982. I'd like to know if USA parts 61 31 1 364 525 and european parts 61 31 1 362 052 are compatible. I saw USA parts (OEM) are in eBay.

thanks!

Coffin

[Tom D]

the same DOT rules may not apply between the U.S. and taiwan, but i doubt BMW would have made the wiring harness any different.

[EconomicHustle]

This is gold. I'll be reviewing it. I have this exact problem... Surprise surprise.

Sent from my SM-G955U using Tapatalk

[jshep79]

Take the switch out, take it apart and fix the problem. It takes about 10 minutes to fix one. it's part of the fun owning one of these cars. Typically the contacts that make the switch catch (called a momentary on off switch) and keep the blinkers from non stop blinking are bent and unable keep the switch in the off position. Take the switch apart bend the contact tab so they catch and release when pressed and pressed again. Put the switch back together and have some pride in knowing you nailed it.

[maxthegearhead]

^^^ jshep79 is totally right. My car is a pre facelift so the fogs and rear defroster are the same type of switch as well, and they were all broken. It's actually kinda fun to rebuild the switches, so much so that whenever i've found E21s in my local junkyards I buy the switches to rebuild and keep as spares!