I've got an old car with central locking that works from switches on both front doors. I was inspecting a switch and it looks like this underneath.
The switch is on all the time (not connected to ignition). I did a little test - when I connect common to up - it unlocks and when I connect common to down it unlocks. Simple enough. So I bought myself a $15 keyless entry kit from ebay and looking at the detailed instructions I'm a bit confused what wires would go where as I don't have the same setup as the diagram.
In my way of thinking I would connect:
black to ground;
red, blue, yellow/black to common (ie positive);
brown to down;
and yellow to up
Anyone played with these kits before? Does this sound about right?
So you're going with the top configuration with the 3 wires same as yours, makes sense to me, that's what I'd try first. The only query is the red wire, common may not be straight to battery, without seeing the cct for the "original controller". If you can't determine if there's anything between common and battery maybe better to run the red to a known positive battery via a fuse, probably only a few milliamps.
First you have to determine if the common on your switch is positive or negative as in a lot of vehicles they switch to negative/ground.
Use a 12v tester and test between 1.your switch common and ground(negative) then 2.your up or down to ground(negative).
If test 1. completes a circuit then switch common is positive(+). If test 2. completes a circuit then switch common is negative(-)
Yellow and brown(up and down) on keyless unit are negative and unit will work with results from test 1. otherwise it aint going to happen
I found a diagram, for an 84 Chevy Coupe. I've got an 88 Chevy Van but the switch looks the same. Unfortunately, my Van is getting the air conditioning replaced cause the idiot up the road put the wrong gas in it, so can't test it. But will test first.
Seems like it's gunna work. I'm assuming the orange wires in the diagram and "hot all the time" means the common wire on the switch is positive
Select to expand quoteoliver said..
I've got an old car with central locking that works from switches on both front doors. I was inspecting a switch and it looks like this underneath.
The switch is on all the time (not connected to ignition). I did a little test - when I connect common to up - it unlocks and when I connect common to down it unlocks. Simple enough. So I bought myself a $15 keyless entry kit from ebay and looking at the detailed instructions I'm a bit confused what wires would go where as I don't have the same setup as the diagram.
In my way of thinking I would connect:
black to ground;
red, blue, yellow/black to common (ie positive);
brown to down;
and yellow to up
Anyone played with these kits before? Does this sound about right?
Nearly correct...
red only to battery + via a fuse
black only to a ground point which is battery -
blue and yellow/black connect together and to the common of existing central locking switch
brown to down
yellow to up
The unit is designed to be universal, the switching part is kept voltage free so you don't have to work out if the individual car is switching the + or the - connecting as above allows the unit to emulate the existing switching unit.
The term common is not referring to either of the battery polaities but is a term for one side of a switch
Ok, I think I'm starting to grasp what's going on. Well nearly.
The other dumb question I've got is about the antenna. Will this work if the unit sits in the door panel?
Does the antenna need to be visible?
I don't even know what technology this switch uses.
Looking at your chevy diagram, I think you can go with your "red to common" idea. Although it's fused at 20A that will probably blow the unit to smithereens if you get a short, I'd add an inline fuse to the red wire, 100mA or 0.1A should do it.
I have my doubts about antenna in door panel, might work close up. The external steel panel is going to block RF fairly well, but the internal door panel probably isn't steel, the antenna may get enough signal from internal reflections.
If you can't find any instructions, it's going to be, "suck it and see."
Select to expand quotedecrepit said..
Looking at your chevy diagram, I think you can go with your "red to common" idea. Although it's fused at 20A that will probably blow the unit to smithereens if you get a short, I'd add an inline fuse to the red wire, 100mA or 0.1A should do it.
I have my doubts about antenna in door panel, might work close up. The external steel panel is going to block RF fairly well, but the internal door panel probably isn't steel, the antenna may get enough signal from internal reflections.
If you can't find any instructions, it's going to be, "suck it and see."
Don't go for the red to common.......... The connections I have described will pick up the correct voltage refernce to switch, no further connection to + or - is required... Definitely put an in line fuse in the red + connection to the unit though.
It comes with an inline fuse. The instructions are what I posted. But then you get what you pay for. May even try to hook up the interior lights to the purple wire maybe they will come on when I unlock/lock. $15 I'm not complaining.
Select to expand quoteSmithy said..
Don't go for the red to common.......... The connections I have described will pick up the correct voltage refernce to switch, no further connection to + or - is required... Definitely put an in line fuse in the red + connection to the unit though.
Well, surely "hot at all times", is +ve battery? Why go to the trouble of going anywhere else?
Unless the battery's a positive earth scenario, and that's easily checked.
I can think of one reason. And I've come across it before and I think it's a reasonably common problem in older cars. May not apply to my central locking though.
When I replaced the sealed beam headlights with the superior halogens. My high beam used to flicker after about a minute. I fixed this by installing relay switches for my headlights and the high beam. The reason is because the wiring is all over the shop, the wires in older cars are too thin/become worn and the small switches in the indicator stick were not designed for new increased load placed on them running the highbeam and the headlights. Installing relays reduced the load on the switch.
Shouldn't connect the 2 Because you have a control circuit that is mA and if the Chevy diagram is correct, a door actuator circuit that is fused at 20amp. The unit is designed to keep the control and door circuits seperate to protect each. If you connect them together the unit will have to be fused at 20 amps which will not protect it and creates a fire hazard as the electronics burnS in the event of a fault...
The other issue of commoning the 2 up is that the electronics may get a switching transient spike when the door actuators operate, this spike can cause the unit to malfunction. If the power supply is seperated and only common closer to the battery this issue is reduced.
as far as going anywhere else, not sure what the issue is, connect a fused 12vdc power supply and run 3 wires to the existing locking switch...
I'll buy the spike from the motor argument, but the red wire has it's own inline fuse, so that shouldn't be a problem.
OK I'm convinced, red wire to a separate batter connection.
Ok, got it all working. Well almost. I just want to do one more thing.
I've got a purple wire that connects to the parking lights. I've found the right fuse and will tap it into the hot side of the fuse.
My question is: If I attach it to the parking lights, is there a danger when the parking lights are on that it could send power back up to my keyless unit causing problems. I'd assume it's probably protected - but for $15 you never know.
As an extra safeguard, and a newby question what type of diode should I attach to ensures the current only goes in one direction - ie from my keyless entry device to the parking lights and not the other way around, when the parking lights are on?
Select to expand quoteoliver said..
Ok, got it all working. Well almost. I just want to do one more thing.
I've got a purple wire that connects to the parking lights. I've found the right fuse and will tap it into the hot side of the fuse.
My question is: If I attach it to the parking lights, is there a danger when the parking lights are on that it could send power back up to my keyless unit causing problems. I'd assume it's probably protected - but for $15 you never know.
As an extra safeguard, and a newby question what type of diode should I attach to ensures the current only goes in one direction - ie from my keyless entry device to the parking lights and not the other way around, when the parking lights are on?
Why do you want to isolate it with a diode? If the diagram shows its for parking lights, then you would hope that they would have thought of that scenario and it won't be a problem. Even though its a $15 part, the original design would have been done by someone knowing their stuff.
How many amps are flowing through your parking lights when they are running? You will typically get a 0.7v voltage drop through the diode, so you want to find out how much current they are using.
Alternatively, run yet another relay from the purple wire, using a fused 12v via a relay to the parking lights. That way there would be no way you can get anything onto the parking lights wire, and its just switched 12v.
Select to expand quoteoliver said..
I can think of one reason. And I've come across it before and I think it's a reasonably common problem in older cars. May not apply to my central locking though.
When I replaced the sealed beam headlights with the superior halogens. My high beam used to flicker after about a minute. I fixed this by installing relay switches for my headlights and the high beam. The reason is because the wiring is all over the shop, the wires in older cars are too thin/become worn and the small switches in the indicator stick were not designed for new increased load placed on them running the highbeam and the headlights. Installing relays reduced the load on the switch.
Yeah, this is normal back when cars didn't have a 1001 relays. When new the switch contacts don't have a problem passing the needed current, but when worn and pitted they do. So every car now seems to have a relay driving almost everything with a decent amount of current.
Select to expand quoteoliver said...
I found a diagram, for an 84 Chevy Coupe. I've got an 88 Chevy Van but the switch looks the same. Unfortunately, my Van is getting the air conditioning replaced cause the idiot up the road put the wrong gas in it, so can't test it. But will test first.
Seems like it's gunna work. I'm assuming the orange wires in the diagram and "hot all the time" means the common wire on the switch is positive
It's a Chevy, why worry about locking it up, not like someone wants to steal it
[;)
Select to expand quoteoliver said..
Ok, got it all working. Well almost. I just want to do one more thing.
I've got a purple wire that connects to the parking lights. I've found the right fuse and will tap it into the hot side of the fuse.
My question is: If I attach it to the parking lights, is there a danger when the parking lights are on that it could send power back up to my keyless unit causing problems. I'd assume it's probably protected - but for $15 you never know.
As an extra safeguard, and a newby question what type of diode should I attach to ensures the current only goes in one direction - ie from my keyless entry device to the parking lights and not the other way around, when the parking lights are on?
Please don't connect the keyless entry system to the hot side of your fuse. At best nothing will happen, at worst (if the keyless entry system switches the negative) you'll blow the system up.
The fuse is normally always powered, the switch and lights come after the fuse. So you need to connect your wire elsewhere, probably after the switch if positively switched. You'll have to check to see whether your system is negatively or positively switched.
Select to expand quotenebbian said..
Please don't connect the keyless entry system to the hot side of your fuse. At best nothing will happen, at worst (if the keyless entry system switches the negative) you'll blow the system up.
The fuse is normally always powered, the switch and lights come after the fuse. So you need to connect your wire elsewhere, probably after the switch if positively switched. You'll have to check to see whether your system is negatively or positively switched.
Yeah you were right. The hot side of the fuse is powered all the time.
With my setup my parking lights are also my indicators and my hazard lights. I've been poking pins through lots of wires now to find the one that will do the job, so far without luck. My next plan is to pull out my dash and examine the light switch and/or the hazard switch and put some more pins in wires to see if I can find a something that will make my $15 keyless entry switch flash the lights when I lock and unlock the van.
So happy I haven't busted something else yet.
