Alarm/starter install Commando FM-870 on 84S
12-01-2005, 01:01 PM
#1
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Thread Starter
Alarm/starter install Commando FM-870 on 84S
I could have lived without this but it was a learning experience and provided satisfaction and convenience and security. So why not? Well here's some of the things I learned. I hope they may help anyone else who wants to accomplish same thing. I installed this in about six hours, not counting planning. The next one would take about half that.
1. Study the "Current flow diagram" for your car. The colors, size and location for wires which you need to find are all in there. The codes such as U2 at the top of the page tell you the wire ends up at terminal 2 of the U plug on the fuse panel board. That could be very good to know.
2. Double check your connections. Solder where you can. I think the best installations are probably all soldered. If you use T-taps, check continuity and connection to the new wire. Sometimes the male spade plug does not engage the tap and you don't notice.
3. Learn about diodes. They will only conduct when their cathode (the end with the stripe) faces ground. They can be used to isolate circuits on seperate fuses such as the parking lights, or to isolate different functions such as the hood pin switch which provides an alarm trigger and a starter kill safety switch.
4. Learn about relays. They can be used to switch large loads with the small signals from alarm unit, reverse polarity, or as in the case of my rear hatch release they provide a switched ground and power from a single negative input.
5. The "power window relay" enables the door locks. It tells the power windows to only work when the ignition is on (mostly) and the door locks to only work when the ignition is off (mostly). This means if you remote start the car you can't unlock it since the ignition is on. My solution was to jumper the relay so the locks (and windows, for now) are powered at all times.
6. Factory alarm disable: for my 1984 US remove Z plug and jumper Z4 to Z6. Other years may use Z1 to Z6 but not mine. The diagrams verify this. Z4 and Z6 are the in/out of a relay in the alarm module which kills power to the ignition system.
Anyway, most won't care about more details. If anyone wants more info, please ask. Others may know better ways to do this than mine and that's good too.
Dave McK.
1. Study the "Current flow diagram" for your car. The colors, size and location for wires which you need to find are all in there. The codes such as U2 at the top of the page tell you the wire ends up at terminal 2 of the U plug on the fuse panel board. That could be very good to know.
2. Double check your connections. Solder where you can. I think the best installations are probably all soldered. If you use T-taps, check continuity and connection to the new wire. Sometimes the male spade plug does not engage the tap and you don't notice.
3. Learn about diodes. They will only conduct when their cathode (the end with the stripe) faces ground. They can be used to isolate circuits on seperate fuses such as the parking lights, or to isolate different functions such as the hood pin switch which provides an alarm trigger and a starter kill safety switch.
4. Learn about relays. They can be used to switch large loads with the small signals from alarm unit, reverse polarity, or as in the case of my rear hatch release they provide a switched ground and power from a single negative input.
5. The "power window relay" enables the door locks. It tells the power windows to only work when the ignition is on (mostly) and the door locks to only work when the ignition is off (mostly). This means if you remote start the car you can't unlock it since the ignition is on. My solution was to jumper the relay so the locks (and windows, for now) are powered at all times.
6. Factory alarm disable: for my 1984 US remove Z plug and jumper Z4 to Z6. Other years may use Z1 to Z6 but not mine. The diagrams verify this. Z4 and Z6 are the in/out of a relay in the alarm module which kills power to the ignition system.
Anyway, most won't care about more details. If anyone wants more info, please ask. Others may know better ways to do this than mine and that's good too.
Dave McK.
12-02-2005, 01:35 AM
#2
Electron Wrangler
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Dave - Good Points all...
Good crimping with new terminals is as good as soldering - this is what Porsche does - soldering is probably a little easier though... no terminal sourcing & removal etc...
There are easier ways to do the hatch... but what you did obviously works too...
Its possible to set the alarm & lock relay to unlock the doors with the ignition on (need to used diodes again) can be a little complicated ...
If you have no problematic issues with the alarm - you can do most of what you implemented with a keyless entry coupled with the existing factory alarm... (usually not the remote start though....)
Sounds like what out did worked out for you - so congratulations!!
Alan
Good crimping with new terminals is as good as soldering - this is what Porsche does - soldering is probably a little easier though... no terminal sourcing & removal etc...
There are easier ways to do the hatch... but what you did obviously works too...
Its possible to set the alarm & lock relay to unlock the doors with the ignition on (need to used diodes again) can be a little complicated ...
If you have no problematic issues with the alarm - you can do most of what you implemented with a keyless entry coupled with the existing factory alarm... (usually not the remote start though....)
Sounds like what out did worked out for you - so congratulations!!
Alan
