04 Yukon crank but no start, no radio, no power windows/locks

[Mortimer452]

Parked my '04 GMC Yukon a couple days ago, 120k miles, working great. Today it won't start. I turn the key to ON position, my gauges cycle and idiot lights come on, but I have no radio, no other dash lights, no power locks, no power windows. If I turn to starting position it will crank just fine, might sputter for a second or two but no start, like it's not getting fuel (assuming fuel pump doesn't have power either).

I've checked nearly every fuse, no luck there. Any other ideas on what might cause this? I briefly checked under steering column for loose wiring but all connectors seems solid, nothing stands out as being loose.

 

[rockola1971]

Check your battery. Whats the voltage at? Atleast 12.5-12.6? All those things listed that arent working correctly dont have a common fuse. They do have a battery, battery ground wire and Ignition Switch in common though. Id check battery then battery connections and then ground wire connection (chassis side).

 

[mwilson62000]

Put a meter on battery? What’s your battery voltage?

 

[Mortimer452]

Put a meter on battery? What’s your battery voltage?

First thing I checked, battery definitely seems good, reads 12.6V, I even put it on a charger overnight just to be sure. It does not struggle in the slightest when I try to start, cranks fast just like any car with a full battery would, just won't start. Sputters a bit like it's trying, but can't get fuel. I assume whatever is preventing the locks/windows/radio from working is also affecting the fuel pump. Unscrewed and re-screwed the battery side connections, they don't look nasty, seem to have good connection. Tomorrow when it's light out I'll check the chassis side ground, maybe that's it, just weird it would still crank fine.

 

[rockola1971]

First thing I checked, battery definitely seems good, reads 12.6V, I even put it on a charger overnight just to be sure. It does not struggle in the slightest when I try to start, cranks fast just like any car with a full battery would, just won't start. Sputters a bit like it's trying, but can't get fuel. I assume whatever is preventing the locks/windows/radio from working is also affecting the fuel pump. Unscrewed and re-screwed the battery side connections, they don't look nasty, seem to have good connection. Tomorrow when it's light out I'll check the chassis side ground, maybe that's it, just weird it would still crank fine.

I am just not finding anything in the schematics that points to a common 12+ wire, fuse or even a module. It all points to the contacts within your ignition switch. It sounds like you have a set of contacts burnt in your ignition switch which would explain all the uncommon stuff that you are having problems with like ignition, radio, fuel pump, dash lights, power windows and locks. If it werent for the engine spinning over fine I would point to the battery or a ground. Luckily the ignition switch is less than $20 and stupid easy to replace.

 

[Mortimer452]

I am just not finding anything in the schematics that points to a common 12+ wire, fuse or even a module. It all points to the contacts within your ignition switch. It sounds like you have a set of contacts burnt in your ignition switch which would explain all the uncommon stuff that you are having problems with like ignition, radio, fuel pump, dash lights, power windows and locks. If it werent for the engine spinning over fine I would point to the battery or a ground. Luckily the ignition switch is less than $20 and stupid easy to replace.

Thanks for this - for $20 I will probably give it a shot before taking to a shop. Will report back here if it works!

 

[Mortimer452]

Replaced ignition switch, unfortunately no change in behavior. It occurred to me that this car has an aftermarket remote start installed (not by me), I'm beginning to wonder if that thing is fried and is causing my issues. Not sure this is something I'm willing to troubleshoot any further, shop is probably my next stop.

 

[rockola1971]

Replaced ignition switch, unfortunately no change in behavior. It occurred to me that this car has an aftermarket remote start installed (not by me), I'm beginning to wonder if that thing is fried and is causing my issues. Not sure this is something I'm willing to troubleshoot any further, shop is probably my next stop.

Well that changes things a bit. Your problem could be there in that module. Throw your used ignition switch back in the jack compartment for an emergency spare!

 

[MassHoe04]

Alarms and those remote start systems usually have a relay and fuse of their own. Typically, they are on the add-on harness somewhere near the control box/brain for the system. Maybe zip-tied to the steering column under the dash or inside the engine compartment. Could be a bad relay, which is about as cheap as you can get, if that is the case.

Maybe you'll get lucky! This is something easy to check out as DIY.

 

[Mortimer452]

Been a few weeks so I thought I would update.

Towed to shop. They were able to get the car to start by running a jumper wire to fuel pump. Car starts and runs, but only the speedo works, no tach, no fuel, no other gauges. Multiple warning lights on dash. No power windows, no radio, no HVAC.

Shop blames aftermarket remote start, tells me to take it to auto electrical shop, at least it drives now so I don't have to pay for another tow, although driving with no HVAC and no ability to roll down windows sucks balls in July heat. I take it to radio shop that did remote start install, they call me the next day and asked how long ago it was flooded? Turns out, ECU compartment and wiring/connectors are all wet, he removed and let them dry out for a day, cleaned up connectors & put on some grease, reconnected and everything works. Car has definitely never been flooded, but we did have some wicked rain a month or two ago and I definitely drove through some water (nothing deep, maybe 4-5" or so), so maybe that's it?

Anyways, here I am a month later, exact same problem happening again, I wonder if that ECU is just fried. What's the best source for a replacement?