Hi guys,

blazer k5 90' with TBI... I'm looking to install a kill switch so it won't be possible to start the truck by short circuiting the starter.

thanks in advance, yarin.

 

without disconnecting the battery of course

 

I'd look at the fuel pump ground.

 

There are several ways you can do this. My favorite, although it won't work on yours, is to add a ground wire and switch to the negative wire on the coil. It'll crank but not start, even when hot wired.

The simplest way on fuel injected systems is a disconnect somewhere in the fuel pump power supply. Put a large, lighted toggle switch on the dash and mark it fuel pump. When the ignition is on and the pump is running, it will be lit. If you want to shut the fuel supply off for work on the engine, this will do fine. However, to avoid unauthorized use of your Blazer, add a hidden switch (unlighted) somewhere between the lit switch and the pump. So if someone is familiar with your truck and tries to use it without your permission, they will see the lit switch but it won't start and they will look elsewhere for the non-start and miss a switch hidden out of sight.

 

actually i already tried to disconnect the fuel pump and encountered an issue i was unable to solve - when the pump ground is disconnected it runs perfectly, i.e. its grounded from another source, unfortunately I'm unable to detect this source..

this brings us to the original question minus the fuel pump

 

Find the wire to the pump and put a cut out in that wire. Pumps can ground out through several paths. You only have one power wire. Messing with the starter wiring can cause major problems down the road. Considering the amperage going through some of the wires, I leave them like the factory wired them. You'd have to get into the rats nest of wires in the dash and find the one activation wire and monkey with it.

 

is it advisable to put a switch on the hot side of the pump?

 

what would be the second best choice after the fuel pump?

 

you can just cut the starter wire coming off the ignition switch under the dash. i want to say its the fat purple one but not sure its been a while, might be the red one. when i bought my 90 pick up i had to put a steering column in it and noticed someone already hacked that wire for a alarm system but the alarm system was removed so i just used that wire and hit the switch somewhere in the cab

 

mmm, switching the wire between the starter and the ignition switch doesn't fulfill my initial request if I'm not mistaken.. i wanted a switch that disables the starter, i.e. cannot start the truck by sticking a screwdriver for example between both poles..