Old School Hot Rodder
Join Date: Feb 2005
Location: Exmore, Va
My Ride: 1986 LeBaron Vert
Engine: MOPAR 2.2L
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Re: Rebirth of T2K-CAR
I had the dash in and out several times to work on the dash harness. The last time was to add all the needed circuits for the BCM features. Two of the interesting ones were wipers and lights. The older cars have the wiper switch as part of the column, actually mounted as part of the pivot for the turn signal switch. They use a small box for the delay feature. After a comparison of the functions I was able to determine that the inner circuitry of the switches were pretty similar. I had an old L-body switch to experiment with and got most of the functions to work except either it wouldn't park, or wouldn't do a complete sweep in the delay mode. I found that (A) the switch ground on the older switch needed to be changed to tie to the low speed wire and (B) both the green wires from the switch needed to go to the DG/WT wire on the BCM pin # 12 and the green wire from the motor park switch to the DG wire on the BCM pin # 10.
The headlight system on the later cars (starting in 1990 on G and J bodies) uses relays and grounds to turn things on. After a couple of tries, I got them working with no false "you left your lights on" warning. The dash light dimming works, but is not really correct as it is apparently a fair sized resistance to ground, and the older pull knob switch works opposite from the later ones. Since I am using the 89 dash, and the 86 body does not have hidden headlights, I mounted a relay module for 5 Bosch type relays in that area. I have park lights, head lights, name brand speaker, and door lock/unlock in it.
Door locks were another issue, the older system is a direct operated system, where the door switches do everything, left door has 5 active terminals. power, two grounds and lock and unlock, right door, the left door lock/unlock go where the left side grounds are and the lock and unlock go to the lock motors on both doors. The 1995 system uses only power and lock/unlock at each door and the lock motors are controlled through relays. This allows a remote keyless entry and anti-theft alarm to be used as options. It also allows an automatic lock feature at a certain speed.
I had the 1989 message center for various warnings, door ajar, low fuel, low washer fluid, trunk ajar. I found I had a crossfeed issue on the door ajar circuits even though the 89 message center uses individual door icons. I added two diodes, one in each wire to the message center, solved! I then addressed the low fuel, older cars use a switch in the sender to activate a delay circuit so you don't get a flashing warning light, and it powers the light when activated. The BCM grounds the light. I had to modify the message center by removing the ground trace and jumping the 12V supply to the opposite side of the light. All of those now work correctly.
1986 LeBaron convertible 2.2L turboII
1986 F350 Crew Cab DRW
2011 Flex Limited