Hazard Switch Repair
Posted: Sun Feb 15, 2009 3:22 am
<B>Repairing the BMW E12 Hazard Switch</B>
<hr>
<br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_01.jpg">
<p>
Here's the emergency flasher from my 1980 528i. These seem to fail in every car, sooner or later. The button pops outward and when you push it back in, it doesn't stay. So now your flashers are on all the time. I had one give way at night, so when I went to start the car the next morning, my battery was drained. Pretty annoying!
<br>Here are some basic instructions on how to fix them when the go Ka-Put.</p>
The general anatomy of this switch in this discussion is;
--->Button; the long forward body of the switch.
--->Bezel; slides over the forward portion of the buttom.
--->Rear Body; the rear contact area that houses the spring.
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_02.jpg">
<p>
<b>TOOLS REQUIRED</B> will be<br>
--->Small slot (bladed) screw driver
--->Pliers, Needle-Nose
--->Diagonal Cutters (aka: dykes or wire cutters)
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_03.jpg">
<p>
Using the screw driver, work it onto the seam and try to separate the front bezel (face portion) from the switch body. <b>BE CAREFUL</b> you can easily slip and STAB your hand if you're not accustomed to this operation; Leather gloves might be a good idea about now.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_04.jpg">
<p>
Once the blade of the screwdriver gets a little separation, slip it under the bezel skirt and lift the rectanular holes up and over the body snaps. Work your way around the lap joint CAREFULLY as to not damage the switch and your fingers.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_05.jpg">
<p>
In separating the fore and aft portions, be aware of an internal compression spring that applies opposing force. One end could "JUMP" off as the spring launches it.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_06.jpg">
<p>
In the body there is a claw pin that rides in a latch guide. This claw pin usually gets over stressed and over time, will bend slightly outward. We need to fix this by using the needle nose plyers and genltly bent it so the claw pin is a little more inward. This causes the pin to extend deeper in the guide for more positive engagement.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_07.jpg">
<p>
Here's a close-up of the claw pin as it has been tweaked inward. Note this doesn't need to be very much. Make the pin come inward about 1/32 to 1/16th if an inch (0.8 to 1.5 mm).
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_08.jpg">
<p>
Remove the compression spring and snip off the last coil on one end. Only do this on ONE END. What we are doing here is reducing the total spring force -- the same force that was overloading the claw pin in the first place. A very cool option is to take the spring down to a hardware store that carries a broad selection of little mechanism springs and try to select one that is the same size, but smaller wire diameter; lower spring rate = lower assembled force.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_09.jpg">
<p>
Remove the front bezel from the button. Make a mental note of how the button fits into the forward bezel.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_10.jpg">
<p>
Okay, <b>HERE'S THE TRICKY PART.</b> With the front bezel removed from the button. We need to assemble the button into the rear body and set the claw pin into the pin guide.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_11.jpg">
<p>
Work the buttom body into the rear body such that the claw pin rides up into the guide and back down so it catches. Got that? This is a two-handed operation, I'm using my other hand to operate the camera.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_12.jpg">
<p>
You must get to this point in the assembly where the pin is caught in the guide; the button and rear body are held together with the claw pin.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_13.jpg">
<p>
Slide the bezel over the button and snap the bezel together with the rear body. Keep track of the alignment tongue and groove.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_14.jpg">
<p>
Here's the switch after snapping it together.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_15.jpg">
<p>
Test the mechanical operation of the switch; push to catch the "IN" position, then push to release to the "OUT" position. Cycle it a few times to make sure it's going to work.<br><br>
CONGRATULATIONS! Now go re-install it in your car.
</p>
<p>
A little off topic; <br>
Reliability is roughly 5 to 10 years; or about as long as regular household light bulb. This switch actually does a good job considering the signal and hazard lights all operate through it. But in this writer's opinion, it should be re-designed to last longer. Here's How:<br>
The spring force is the main issue. In NORMAL operation, with the button pushed in, the spring force is HIGH, it over loads the claw catch and the plastic guide. When the button is popped OUT, the blinking hazard mode is on -- Spring load is reduced, but only during the hazard-blink mode. One fix is to reverse the operation mode where the standard operation of the button is OUT (less spring load) and more fail-safe scenario. Press the button in to operate the hazard (like most cars today have). If they choose to keep the same design to prevent redesign and tooling/manufacturing costs, then change out the spring with another of the same size, but smaller diameter to impart a lower switch force.
<br>Hope the BMW engineers take note of this!
<hr>
<br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_01.jpg">
<p>
Here's the emergency flasher from my 1980 528i. These seem to fail in every car, sooner or later. The button pops outward and when you push it back in, it doesn't stay. So now your flashers are on all the time. I had one give way at night, so when I went to start the car the next morning, my battery was drained. Pretty annoying!
<br>Here are some basic instructions on how to fix them when the go Ka-Put.</p>
The general anatomy of this switch in this discussion is;
--->Button; the long forward body of the switch.
--->Bezel; slides over the forward portion of the buttom.
--->Rear Body; the rear contact area that houses the spring.
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_02.jpg">
<p>
<b>TOOLS REQUIRED</B> will be<br>
--->Small slot (bladed) screw driver
--->Pliers, Needle-Nose
--->Diagonal Cutters (aka: dykes or wire cutters)
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_03.jpg">
<p>
Using the screw driver, work it onto the seam and try to separate the front bezel (face portion) from the switch body. <b>BE CAREFUL</b> you can easily slip and STAB your hand if you're not accustomed to this operation; Leather gloves might be a good idea about now.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_04.jpg">
<p>
Once the blade of the screwdriver gets a little separation, slip it under the bezel skirt and lift the rectanular holes up and over the body snaps. Work your way around the lap joint CAREFULLY as to not damage the switch and your fingers.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_05.jpg">
<p>
In separating the fore and aft portions, be aware of an internal compression spring that applies opposing force. One end could "JUMP" off as the spring launches it.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_06.jpg">
<p>
In the body there is a claw pin that rides in a latch guide. This claw pin usually gets over stressed and over time, will bend slightly outward. We need to fix this by using the needle nose plyers and genltly bent it so the claw pin is a little more inward. This causes the pin to extend deeper in the guide for more positive engagement.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_07.jpg">
<p>
Here's a close-up of the claw pin as it has been tweaked inward. Note this doesn't need to be very much. Make the pin come inward about 1/32 to 1/16th if an inch (0.8 to 1.5 mm).
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_08.jpg">
<p>
Remove the compression spring and snip off the last coil on one end. Only do this on ONE END. What we are doing here is reducing the total spring force -- the same force that was overloading the claw pin in the first place. A very cool option is to take the spring down to a hardware store that carries a broad selection of little mechanism springs and try to select one that is the same size, but smaller wire diameter; lower spring rate = lower assembled force.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_09.jpg">
<p>
Remove the front bezel from the button. Make a mental note of how the button fits into the forward bezel.
</p>
<br><br><hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_10.jpg">
<p>
Okay, <b>HERE'S THE TRICKY PART.</b> With the front bezel removed from the button. We need to assemble the button into the rear body and set the claw pin into the pin guide.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_11.jpg">
<p>
Work the buttom body into the rear body such that the claw pin rides up into the guide and back down so it catches. Got that? This is a two-handed operation, I'm using my other hand to operate the camera.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_12.jpg">
<p>
You must get to this point in the assembly where the pin is caught in the guide; the button and rear body are held together with the claw pin.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_13.jpg">
<p>
Slide the bezel over the button and snap the bezel together with the rear body. Keep track of the alignment tongue and groove.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_14.jpg">
<p>
Here's the switch after snapping it together.
</p>
<hr><br><br>
<img src="http://www.geocities.com/tunaoue/FirstF ... HER_15.jpg">
<p>
Test the mechanical operation of the switch; push to catch the "IN" position, then push to release to the "OUT" position. Cycle it a few times to make sure it's going to work.<br><br>
CONGRATULATIONS! Now go re-install it in your car.
</p>
<p>
A little off topic; <br>
Reliability is roughly 5 to 10 years; or about as long as regular household light bulb. This switch actually does a good job considering the signal and hazard lights all operate through it. But in this writer's opinion, it should be re-designed to last longer. Here's How:<br>
The spring force is the main issue. In NORMAL operation, with the button pushed in, the spring force is HIGH, it over loads the claw catch and the plastic guide. When the button is popped OUT, the blinking hazard mode is on -- Spring load is reduced, but only during the hazard-blink mode. One fix is to reverse the operation mode where the standard operation of the button is OUT (less spring load) and more fail-safe scenario. Press the button in to operate the hazard (like most cars today have). If they choose to keep the same design to prevent redesign and tooling/manufacturing costs, then change out the spring with another of the same size, but smaller diameter to impart a lower switch force.
<br>Hope the BMW engineers take note of this!
using a small pin to hold it in now
