Progress Thread Therapy Car - wiring issues

kendawg73

Active Member
Feb 5, 2014
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So, your going to put a new keyless entry system in right? I would like to do this too (spoiled with the newer cars, I'm still keeping my key locks though)... let me know what you find/use....
 
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Olivethefet

Active Member
May 17, 2018
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Enterprise AL
That's the idea. Then maybe I won't be so paranoid about locking myself out of the car. I'm going to try to document as best I can. I would highly recommend never removing the actual exterior locks from your vehicle unless its some kind fancy show car or something.
 

Olivethefet

Active Member
May 17, 2018
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Enterprise AL
I was thinking about trying to rig up a way to pop the hood from outside the car. Just in case the battery dies. I do have a lockout kit if it comes to it. I got pretty good at unlocking my friends cars when they locked the keys in their car.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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BMW puts a positive battery connection under the car on the drivers side, BMW will not tell you that, they will charge you $150 bucks to open it, thats after you pay the tow truck to take it there. The door locks are solenoid operated so door tools don't work on them.
just put a positive battery connection under the front some place, they make them with a jiffy little red cap to cover it.
 

Olivethefet

Active Member
May 17, 2018
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Enterprise AL
Definitely going to install a battery connection on the car that I can get to with the hood and and doors locked. That was an awesome idea.

After doing some digging around on the site I came up with this helpful wiring diagram.

Power door lock diagram - typical 87-90 Mustang.jpg


From everything that I can come up with the motors are grounded by attaching them to the door frame. There is constant hot going to the lock/unlock switches. When you hit lock or unlock it sends positive voltage to one side of the motor or the other. Depending on the side it either locks or unlocks the doors. Simple enough. The kit that I bought sends an impulse signal, but it can take the voltage, so you need a relay. I found this diagram for wiring up the relays.

Edit. I removed this diagram so that I didn't forget to in the future and accidentally cause someone else down the road confusion. The diagram in the link are good reference material so I'll leave the link.

Here is a link to the website.
https://www.the12volt.com/doorlocks/multiple-wire-car-door-locks.asp#5w

Soooo, last night I wired the relays up as shown above and spliced them into the factory wiring harness. Keep in mind that my harness had already been hacked before it got to me, so I wan't doing any new damage. I wasn't trying to do the permanent install, just see if I could get the unit to lock and unlock the doors. The factory harness wire is #10 or #12 wire intended to carry a higher load. All I had on hand was some #16. The intent was to use it once or twice then do the permanent install with heavier wire. Long story short it didn't work. When I hit the drivers side lock button in the car it straight smoked the wires on the relay, burned the rocker switch up and locked both door lock actuators in the locked position. Thank God I had the good since to open the doors before experimenting. When I get home tonight I'm going to dig further into it to see what happened and to figure out the replacement parts list. Any idea what I did wrong? My car is a 92 if it makes a difference.

Once I get this all straight and working I'll take some good pictures of the end product so that people can see what wires get cut and how to wire the relays. Drawings are nice but pictures really help.
 
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Olivethefet

Active Member
May 17, 2018
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Couple of pics of the relays minus the burnt wires. Really only one of them burned. This was only temporary never intended to be an end product.

20190212_173924.jpg 20190212_173930.jpg
 
May 17, 2018
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Pretty sure I'm a moron. 99% sure I know what I did wrong in the wiring. I toasted the driver's side lock switch, ordered a replacement last night along with some other stuff. When I get everything in I'll see if I really did learn from my mistake.
 
May 17, 2018
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This is how I have my relays wired up.

5wap.gif
When I first wired it up the door locks worked using the switches on the door, but when I try to use the key fob the relays click but the doors do not luck or unlock. Now the switches don't want to work. This seems fairly straightforward but its kicking my butt. Any ideas of what I'm doing wrong?
 
May 17, 2018
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Still working on what's going on with the locks. In the meantime I got to looking at the under hood wiring. I found the the mass air harness had been rewraped, and didn't look quite right. I unwrap it and found that the shielding had been stripped in on the wires and jumper wires had been spliced in. I've got no idea why this was done. Any idea? Now I'm trying to decide if I want to just wrap the skint wires with electric tape or if I should cut out the bad and solder them back I together. What do you guys think?
20190218_215110.jpg
 
Jul 7, 2005
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Definitely do it right and solder and heat shrink. It isn't much fun when down the road the tape comes off exposing those wires again.
 

02 281 GT

Agreed...My wife has great Boobs
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Feb 3, 2009
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Get yourself some heat shrink that is lined with adhesive. That'll provide even more corrosion protection.

Adhesive-lined heat shrink came in the Motorcraft wiper motor kit I used to replace the original on my Mercury (to adapt a later single plug motor on my car that originally came with a two plug motor).
oUoX4MA.jpg
 
May 17, 2018
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Great advice! I'll look for some of that. I have regular heat shrink.

Man these door locks are kicking my butt. Apparently I have some kind of ground issue.
 

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