Selector switch
Link to other parts of the project
Project ZF 5HP19 transmission
On the side of the transmission is a large switch. This is what tells the car which gear has been selected. You may need to replace this if it fails, or if you are like me, you will want to pull it apart, find out what is wrong with it and fix it.
If it fails, you will get an OBD code saying that the switch is giving an invalid value, and the transmission will go into limp mode (stuck in 4th gear). Unfortunately I know this because my wife’s Audi (which has a 5HP19 transmission) had this issue. Fortunately for BMW owners, the switch is easily accessible from under the car. On the Audi it’s a nightmare but that’s another story. I think I’ve mentioned before in other posts that the BMW is far easier to work on than the Audi, and a miles better car. I’ll mention it again. Our problem was fixed by having the engine off, but the ignition turned on, and then running the gear lever back and forth through all the gears over and over about a hundred times. The car hadn’t been started for about 6 months (due to us living overseas) and I think some of the contacts maybe got some moisture in them and corroded a little. Who knows? It now works, and I didn’t have to pay Audi $800 for a new switch, and about $1500 in labour to fix it. Did I also mention that Audi charge about twice as much for the same parts as BMW?
If you do have a problem with the switch, here are some photos that might help in pulling it apart and fixing it. Disconnect the gear select cable and then remove the switch. Unfortunately the switch is riveted together. Drill the rivet heads off, and then knock them out. To put it back together you can rivet it if you like, or do what I did. Get some small nuts/bolts and with a little loctite have it back like new. Don’t worry about the heads of the bolts sticking out, there is plenty of room on each side of the switch for the other components that are around it.
Having now pulled a few of these switches apart it seems there are two different varieties. On the outside they look the same, but internally they are very different. The earlier variant looks like the images below. The later variant has a number of wiper arms that swipe across brass strips that give the indications of gear selection. Opening and closing the switch is identical, but the wiper variant can generally be fixed by cleaning away some of the grease that restricts connection and bending the arms slightly so they give better contact.
Link to other parts of the project
Project ZF 5HP19 transmission
On the side of the transmission is a large switch. This is what tells the car which gear has been selected. You may need to replace this if it fails, or if you are like me, you will want to pull it apart, find out what is wrong with it and fix it.
If it fails, you will get an OBD code saying that the switch is giving an invalid value, and the transmission will go into limp mode (stuck in 4th gear). Unfortunately I know this because my wife’s Audi (which has a 5HP19 transmission) had this issue. Fortunately for BMW owners, the switch is easily accessible from under the car. On the Audi it’s a nightmare but that’s another story. I think I’ve mentioned before in other posts that the BMW is far easier to work on than the Audi, and a miles better car. I’ll mention it again. Our problem was fixed by having the engine off, but the ignition turned on, and then running the gear lever back and forth through all the gears over and over about a hundred times. The car hadn’t been started for about 6 months (due to us living overseas) and I think some of the contacts maybe got some moisture in them and corroded a little. Who knows? It now works, and I didn’t have to pay Audi $800 for a new switch, and about $1500 in labour to fix it. Did I also mention that Audi charge about twice as much for the same parts as BMW?
If you do have a problem with the switch, here are some photos that might help in pulling it apart and fixing it. Disconnect the gear select cable and then remove the switch. Unfortunately the switch is riveted together. Drill the rivet heads off, and then knock them out. To put it back together you can rivet it if you like, or do what I did. Get some small nuts/bolts and with a little loctite have it back like new. Don’t worry about the heads of the bolts sticking out, there is plenty of room on each side of the switch for the other components that are around it.
Having now pulled a few of these switches apart it seems there are two different varieties. On the outside they look the same, but internally they are very different. The earlier variant looks like the images below. The later variant has a number of wiper arms that swipe across brass strips that give the indications of gear selection. Opening and closing the switch is identical, but the wiper variant can generally be fixed by cleaning away some of the grease that restricts connection and bending the arms slightly so they give better contact.