2nd gen 4Runner power door lock actuator melt down, Why? (1 Viewer)

Joined
Jan 11, 2009
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I've had this 1990 4Runner going on over 30 years now. One fine day about 20 years ago, I locked the doors with the remote fob and when I came back later that afternoon I could not get any of the doors to open with the fob or with the key. Thank goodness for the roll down back window. The issue ended up being all four of the door lock actuators had catastrophically melted down. At the time the dealer wanted a crazy $$$ to replace all the actuators and would not guarantee the issue wouldn't reoccur. I ended up pulling all the actuators out of the doors myself and have just operating the door locks manually since. Over the years the doors have gotten pretty rusty from kayaks dripping salt water and I have just recently acquired four rust free doors with working actuators. I am a bit hesitant to put them on without knowing what caused the original door lock actuators to melt down. My guess is that it may have been caused by a sticking contact in the door lock relay, but maybe it could have been a sticking fob button or something haywire with the dealer installed alarm system. I only found one other account of a similar incident on a 2nd gen in my internet searches, but no definitive root cause was given. Has anyone else had a similar door lock actuator issue on a 2nd gen and if so, did you find out what caused it and was there a fix that has lasted long term?
Thanks,
 
Joined
Jul 19, 2015
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Location
CO
Did you ever look into the Door Lock Relay?
I am skeptical that all four solenoids went out on their own. You can pull those units off (those clips that grip the rods are a bugger) and test them direclty with a 12V. Simple reverse polarity. Also IIRC the relay actually controls the gounding of the locks (not to mention the interior light).

Also check all those grounds.
 
Joined
Jan 11, 2009
Messages
119
I
Did you ever look into the Door Lock Relay?
I am skeptical that all four solenoids went out on their own. You can pull those units off (those clips that grip the rods are a bugger) and test them direclty with a 12V. Simple reverse polarity. Also IIRC the relay actually controls the gounding of the locks (not to mention the interior light).

Also check all those grounds.
To update, the used doors I ended up getting were off a 94 4Runner. Toyota apparently made some significant changes to the power door lock system on the later 2nd gens. I am thinking they changed from solenoid style to an electric motor and worm drive configuration. Anyway, I had to splice about 9 or so wires on the wiring harness of the front doors for the power locks. The wires were the same colors, just the two connectors and what they connected to were significantly different. The only other electrical connector difference was the power mirrors. The good news is that the power locks on all 4 newer doors I installed are working. I have not even wanted to try the alarm key fob for concerns that something with the alarm system may have been involved with the solenoid melt down. I am just very happy that the power locks are working now.
 

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