We have a probelm with our 5.3 Silverado that is very strange.

The truck cuts out electrically meaning the engine dies suddenly.
It doesn't feel like for example a fuel problem where the ignition wants to work, but it's starving for gas- it just dies like the key is shut off.

At first it seemed to happen when using either the turn signals or high beams, so we replaced the turn assembly on the column. The old assembly looked like there was one terminal that had gotten a little toasty, so we figured we had it- unfortunately the truck is still dying.

When it does it, there is a relay under the dash(?) that clicks after it dies.

Unhooking the battery, and reconnecting it solves the problem, meaning no relay clicking, and it starts and runs like it should.

There are no computer codes, and no fuses are blowing.

Any ideas?

THANKS!

Welcome to AF.
Check all battery cables and ends ends and grounds and power feeds from battery on up to underhood fuse box.
MT

Thanks-

I've already checked the supply cable issues, down to measuring with a DMM at each end of the cable (to ensure that although they *look* OK, they aren't corroded inside the terminations).

The relay clicking under the dash is curious. Is there a "master" relay after the key in the column that in turn feeds relays for the fuel pump, IGN, etc?

It's almost as if this relay is getting stuck in a state where it can't completely turn on or off, and keeps cycling... unless it's a computer error that is causing this relay to click...(?)

Check for 12 power on into fuse block.
MT

What do the exterior and interior lights do when this happens? If they go out also it's most likely a power and/or ground feed problem from the batt. If they stay on it's most likely an ignition switch and/or wiring. Since you say it sometimes happens with movement of the multi-function switch that's the area in the column were I'd start looking.

There is no "master" relay and I'd say when you get the cutting-out fixed it will cure the clicking relay.

As far as "testing" the batt cables. They may test good for resistance but not be able to carry the amperage load. JMHO

What do the exterior and interior lights do when this happens?
As far as "testing" the batt cables. They may test good for resistance but not be able to carry the amperage load. JMHO
>>>>>>>>>
All of the lights stay on, you just can't restart it- sometimes the gauges "flip out" meaning wildly flutuating, and the relay clicking noise.

I had measured the voltage at each end of the cables, but I understand the point that even though the voltage is OK when not under demand, they may not be able to pass enough current under load.

I'm going to more carefully comb through the circuits today. We were able to replicate the symptom before replacing the multi function switch just by working the multi function switch. However, I am not discounting the possibility that replacing the switch just changed things by disturbing a wire that was partially pinched off, or shorted.

The fact that a fuse(s) aren't blowing tells me that it might not be a short to ground if in fact it is a wire.

*sigh* fun

Thanks guys

>>>>>>>>>
All of the lights stay on, you just can't restart it- sometimes the gauges "flip out" meaning wildly flutuating, and the relay clicking noise.

I had measured the voltage at each end of the cables, but I understand the point that even though the voltage is OK when not under demand, they may not be able to pass enough current under load.

I'm going to more carefully comb through the circuits today. We were able to replicate the symptom before replacing the multi function switch just by working the multi function switch. However, I am not discounting the possibility that replacing the switch just changed things by disturbing a wire that was partially pinched off, or shorted.

The fact that a fuse(s) aren't blowing tells me that it might not be a short to ground if in fact it is a wire.

*sigh* fun

Thanks guys

You need to get into the underhood fuse box and all ign power feeds and check for lose of power.
It is losing power/12 volts someplace.
If the multi function switch changed things go back in there and look around.
Does it still make any difference when you use the multi function switch or raise and lower steering wheel/column?
MT