Lexus LX450 - no crank / alarm issue? (1 Viewer)

Joined
Jul 22, 2015
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383
Location
Tampa, FL
Doing some work on a 96 LX450. Previous owner had both the factory Toyota RS3000 and some aftermarket junk alarm wired in. It had intermittent start problems, between hitting the valet switch and remote buttons in a random sequence I could get it started, but for simplicity I have now removed the factory and aftermarket alarm systems from the truck. I don't see any additional cut wires, and all the plugs are plugged in. I have power and check engine light illuminated, but no crank. If I run a wire from the battery to the start signal on the starter itself, it turns over and runs perfectly. I have some sort of disconnect between the ignition switch and the starter. When I test voltage at the ignition switch plug, I have 12V at the proper places, the thing that has me stumped is I have 10V at the starter signal wire in the "on" position. When I turn the key to "start" that 10V B-W wire goes to 12V. Is that normal? What else could I check? Any tips would be helpful :) Here's what I'm using for a wiring diagram right now.

Untitled by CA18 Sean, on Flickr
 
Joined
Nov 9, 2012
Messages
10,719
Location
Olathe, KS, USA
I would check the fusible links (replace unless having been recently replaced).

Second, check the wire connections and battery cables to make sure they are good. Possibly due to work, one got moved and has lost connection.
 
Joined
Jul 22, 2015
Messages
383
Location
Tampa, FL
I left the signal wire connected from the battery to the starter post and it fires every time, no problem, no hesitation. I think we can rule out wires or battery. I believe this is a cut wire under the dash or bad ignition switch. Possibly bad neutral safety switch. But the fact that I could start it normally sometimes before I removed the alarm leads me to believe it's some cut wire that the alarm installer did to make the alarm able to kill the starter when activated.
 
Joined
Jul 22, 2015
Messages
383
Location
Tampa, FL
Found it, loose connection with the factory start signal plug. The black plug clicks into place but wasn't making a good connection. Disconnected and checked with a multimeter, saw 12V at starter. Filled with dielectric grease and it seems to be working properly now.
 

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