I found the Intermittent parasitic load

[Geo-TH,In]

I'm convinced my 2007 GMC work truck has Gremlins.
Yesterday I got lucky. I measured a 1 amp drain and traced it back to the cruise control.
The darn Gremlins are trying to use the cruise control when the truck is parked in the garage.
By the way, the cruise worked fine before I removed the fuse.
Why didn't the cruise control turn off then the key is off?

 

[olddavid]

Good question. Maybe it goes through a relay and the relay contacts stuck closed.

 

[40Mule]

I worked on a 2003 impala, fourteen years old and 16,000 miles. It did similar things as you have described. Mother in laws. Battery dead. Took it to dealer and described symptoms. Replaced battery though it was a year old. Took it home and next morning battery dead. After much internet research, I took it to dealer and told them to replace Body Control Module. Behind end panel of dash when you open the drivers door. Plastic appeared degraded when I looked at it. In MY case, The Module has to be programmed to that specific vehicle. It was NONerasable where if a mistake was made in programming it could not be changed. That is why I had the dealer do it. May have been over five hundred to get it fixed. I drove it to 40,000 miles and then gave it to granddaughter that drives it everywhere. Not one further problem. The lights would flash on it, trunk latch would click non stop and various dashboard messages. When it was cool outside or sat in the garage it seemed to work properly, but if it sat out in the hot sun it would go crazy. Wife said it was possessed and I was starting to believe her. Hope this helps.

 

[wore out]

I'm convinced my 2007 GMC work truck has Gremlins.
Yesterday I got lucky. I measured a 1 amp drain and traced it back to the cruise control.
The darn Gremlins are trying to use the cruise control when the truck is parked in the garage.
By the way, the cruise worked fine before I removed the fuse.
Why didn't the cruise control turn off then the key is off?

George, you DIDN'T find the PROBLEM, you found the RESULT of the problem.

The various electronic systems in your truck "talk" to each other over a pair of wires using a version of CANBUS.

When you switch the ignition "OFF" most things are supposed to "power down" over a minute or two.

If one (or more) of the modules has an issue the proper commands don't get sent though the system and some things don't shut down properly.

As I told you before, the instrument cluster can be involved (it has it's own processor and failed solder joints are COMMON on it's circuit board) or the "BCM" (body control module), or even the ignition switch. At some point, there was an issue with ignition switches and the replacement was an entirely different part and part number.

The talk of "gremlins" is SILLY, have the vehicle scanned with a dealer-level scan tool and see what comes up. More than likely some clues will be found in that info.

Also, fire up the GOOGLE machine and look up the various causes of battery drain for you make, model, and year.

 

[Geo-TH,In]

George, you DIDN'T find the PROBLEM, you found the RESULT of the problem.

The various electronic systems in your truck "talk" to each other over a pair of wires using a version of CANBUS.

When you switch the ignition "OFF" most things are supposed to "power down" over a minute or two.

If one (or more) of the modules has an issue the proper commands don't get sent though the system and some things don't shut down properly.

As I told you before, the instrument cluster can be involved (it has it's own processor and failed solder joints are COMMON on it's circuit board) or the "BCM" (body control module), or even the ignition switch. At some point, there was an issue with ignition switches and the replacement was an entirely different part and part number.

The talk of "gremlins" is SILLY, have the vehicle scanned with a dealer-level scan tool and see what comes up. More than likely some clues will be found in that info.

Also, fire up the GOOGLE machine and look up the various causes of battery drain for you make, model, and year.

wore out.
Would you like to come over and find my drain??
Truck's EMC was scanned and nothing.
Please find my GREMLINS!!!

 

[olddavid]

That's the trouble with the new "improved" technology. You used to have wiring gremlins but now you have micro processor gremlins added to those. Ain't technology wonderful? Did they scan the body computer(s)? If its just the cruise control module and you don't use cruise you might consider just unplugging it and see if that takes care of it. If it's a computer problem that's another story.

 

[wore out]

wore out.
Would you like to come over and find my drain??
Truck's EMC was scanned and nothing.
Please find my GREMLINS!!!

Was it scanned at a dealership, or at least with a "high end" scan tool?

IMHE, there's going to be at least some data in there related to CANBUS communications issues, IF one digs deep enough into all the PID information turned up by such a tool.

 

[wore out]

Was it scanned at a dealership, or at least with a "high end" scan tool?

P.S., did you check on the 'net for info on any of the common issues I mentioned that affect GM trucks of the era of yours?

 

[Geo-TH,In]

That's the trouble with the new "improved" technology. You used to have wiring gremlins but now you have micro processor gremlins added to those. Ain't technology wonderful? Did they scan the body computer(s)? If its just the cruise control module and you don't use cruise you might consider just unplugging it and see if that takes care of it. If it's a computer problem that's another story.

Computer was scanned when check engine light was on, nothing shows up then engine light goes off.
I'm not 100 percent certain of anything except myl only drain is 30 ma
Not 1 amp.

 

[wore out]

Computer was scanned when check engine light was on, nothing shows up then engine light goes off.
I'm not 100 percent certain of anything except myl only drain is 30 ma
Not 1 amp.

You still haven't told us where or with what type of scanner it was checked?

 

[MarkB_MI]

Interesting. So is the problem truly intermittent? A one amp draw is a bunch,

As David suggested, I'd look for stuck contacts on any relay associated with the cruise control.

 

[showcrop]

Interesting. So is the problem truly intermittent? A one amp draw is a bunch,

As David suggested, I'd look for stuck contacts on any relay associated with the cruise control.

Yes, one amp is a very big draw. Anything that is drawing that much should be generating heat.

 

[olddavid]

I did a bit of looking on the internet and couldn't find a relay in the cruise control circuit, at least a visible one. I never found a schematic that showed the whole circuit clearly. I think "40Mule" and "Wore out" may be more on track except now George you are saying that the off current draw is only 30 ma. I think that is typical for modern cars and pickups. Did you actually have a 1 amp draw at first and now it's only 30 ma.? If so, it may be intermittent.

 

[oldsarge]

George, you DIDN'T find the PROBLEM, you found the RESULT of the problem.

The various electronic systems in your truck "talk" to each other over a pair of wires using a version of CANBUS.

When you switch the ignition "OFF" most things are supposed to "power down" over a minute or two.

If one (or more) of the modules has an issue the proper commands don't get sent though the system and some things don't shut down properly.

As I told you before, the instrument cluster can be involved (it has it's own processor and failed solder joints are COMMON on it's circuit board) or the "BCM" (body control module), or even the ignition switch. At some point, there was an issue with ignition switches and the replacement was an entirely different part and part number.

The talk of "gremlins" is SILLY, have the vehicle scanned with a dealer-level scan tool and see what comes up. More than likely some clues will be found in that info.

Also, fire up the GOOGLE machine and look up the various causes of battery drain for you make, model, and year.

What happens and how do you know when the scan tool goes bad ?? I'm serious !!!!!!

 

[Geo-TH,In]

I did a bit of looking on the internet and couldn't find a relay in the cruise control circuit, at least a visible one. I never found a schematic that showed the whole circuit clearly. I think "40Mule" and "Wore out" may be more on track except now George you are saying that the off current draw is only 30 ma. I think that is typical for modern cars and pickups. Did you actually have a 1 amp draw at first and now it's only 30 ma.? If so, it may be intermittent.

The truck is only used occasionally for local trips.
No Biggie if the Cruise works or not.
Hope this solves my battery draining.
Time will tell.