Most modern alarms and keyless entry use the relays in the car. I am sure someone somewhere has created one with the relays internal but typically any modern car with power door locks will have relays and if youre adding power doorlocks, its assumed you will add relays. Older cars are different.. They are typically have hard wired connections that dont use relays.. I am pretty sure your car will need the relays. In some cases (modern cars) you tap into the BCM (body control module) which controls the locks but those have the relays internal so youre just accomplishing the same thing in a different manner. When I had my fox, im almost positive I had to add relays for the lock and unlock to work with the alarm. Its been over 20 years since I was an installer, its pretty difficult to remember specifics...
Now that I think about it, I am positive there are alarms with the relays built in. They require less wiring but still require you to cut the existing lock/unlock wires and put the alarm inline. The reason for this is because its a reverse polarity design.
thats correct.. Fox mustangs dont use relays, they use hard wired switches with large gauges so they dont need relays. I think 05 is the first year with a body control module with relays built in. You will either need to add relays in line which is really easy or you can try to find a keyless entry with relays built in. In either case you will need to cut the power door lock wires down in the kick panel and wire the relays inline or wire the alarm inline. I would use relays because its easy and it will not limit your choices. In my experience the name brand alarms and keyless systems require you to use relays.
Got a 2101L system, going to be installing it probably couple weeks. Where do people normally mount the module and then the 3 relays? Two relays for the doors, one for the hatch release. I don't see a lot of space under the dash.
I have that same Avital Keyless Entry System and hooked it up last fall. I only did the door locks... still need to install a separate relay for the Hatch Release. The main unit installs behind the drives kick panel and has internal relays for the doors. So all you do is cut the 2 existing wires and add the new connections. Be sure to test it before soldering, because I didn't and had to redo it when the button functions were somehow reversed. Here are my old install notes.
DOOR LOCK Wiring, Drives Kick Panel
[LOCK] Circuit: cut PINK/YELLOW
Module H1/6 WHITE/BLACK (Internal Relay #87a Normally Closed) to PINK/YELLOW towards switch
Module H1/5 GREEN/BLACK (Internal Relay #30 Common Output) to PINK/YELLOW towards motor
Module H1/7 VIOLET/BLACK (Internal Relay #87 Normally Open Input) to 12V Constant Power Input
[UNLOCK] Circuit: cut PINK/LIGHT GREEN
Module H1/17 BROWN/BLACK (Internal Relay #87a Normally Closed) to PINK/GREEN towards switch
Module H1/8 BLUE/BLACK (Internal Relay #30 Common Output) to PINK/GREEN towards motor
H1/9 VIOLET (Internal Relay #87 Normally Open Input) to 12V Constant Power Input
Module H1/18 RED/WHITE (-) Output of Channel 2 (trunk) BLACK (#85) of external Relay
RED wire from Relay (#87a) to switch side of PURPLE/YELLOW wire
BLUE wire from Relay (30) to motor side of PURPLE/YELLOW wire towards trunk
WHITE (#86) & YELLOW (#87) wire is fused (10 amp) to 12+ volts
Module H1/10 WHITE wire to Brown Parking Lights at Light Switch
Module H1/1 RED (+) 12V Constant Power Input
Module H1/11 BLACK (-) Chassis Ground
I got it all done. It's not really "that" bad, particularly since the entire interior was already out of the car, so I could lay down on my side on the floor with the seat removed. This makes it go a little easier. I picked up a towing harness that was talked about in another thread, and used that. Using that, only had to do basic connections, plug it in and go. The only issue I ran into was that I also wanted the dome light feature to work (holds the courtesy lights on after you shut the door, for 30 sec or until you turn the key on), I had to cut a couple wires to make that work. Not too bad at all. Did not use the horn function. Door locks and hatch release are all I used but it will also function as a remote start for those users that might want that (I did not). Worst part is finding a place to stuff the module into. I have it stuffed pretty tight behind the kick panel with the other connectors; it's tight in there once the kick panel is attached properly.
Thanks TomV for the instruction on the wiring; simplified the install--and the simpler the better (for me).
avital has the wiring instructions in their booklet which I find to be informative but it does not tell you what wires in the car to attach to, etc., because the avital unit is universal.
One thing I don't like is that when opening the hatchback using the remote, you have to hold the button on the remote for like 3 seconds. Seems like forever. I thought it might work more immediate kinda like OEM stuff does but I guess that is not the case. I can live with it just fine, though. Just an oddity is all. Another thing I didn't care for was that auto locks are standard, so when you turn the key on, the doors automatically lock and then when you turn the key off, they automatically unlock. I turned that feature off; I hate it.
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