I've been working on diagnosing a battery drain in a 04 Blazer.

Here's what I know so far:

- battery drains after vehicle sits for several hours

- current battery has been drained many times but was replaced several months ago in an attempt to correct this problem

- 0.9 A current draw when ignition is in the off position

- removing one of the radio fuses brings current draw down to 0.2 A

- removing courtesy light fuse brings current draw down to 0.1 A

- when radio fuse is removed IP cluster gauges stop working

I'm not certain that the 0.9 A draw is the same current which is draining the battery. The ignition switch has known issues. Prior owner said the battery drains if the ignition is left in certain positions after key is removed.

I measured current through ignition switch with a current clamp and did not find any significant draws.

For starters I'd like to figure out what the 700 mA draw is that disappears when the radio fuse is removed. There is no radio in the vehicle and I've verified all radio wires in the dash are taped off and insulated from each other at their ends.

Thanks.

David.

 

Hmm, thats a tricky one with no radio.
Im working on figuring out a battery drain of my own that started up 2 days ago.
I am impressed how much you already have figured out about the problem, lots of the time a post is made in frusturation before any investigation has taken place.
Wish i could help with that.

GL tracking that down!

 

could be a bad alternator

did you notice if the volt meter is showing a higher charge?

 

I had the same problem with my wifes 97 Blazer. Replaced the ignition switch and it solved the problem.

 

I have the same issues on a 97 blazer. It use to be if it sat over the weekend without being started the battery would be dead Mon. morning. Now it goes dead over night. I've got the same ignition switch problem that is common on blazers, I've got a new switch just waiting for time to change it. The other day
I had trouble starting it while I had the hood opened I noticed that the red wire on the + post had burned in two. I twisted the ends together(there was a good spark when they touched)and it started right up. My twist job didn't last long, the strands of wires were all brittle and burnt. I made a jumper wire and this has worked fine, but the battery still went dead over night. Now here's some thing curious if I unhook the jump wire when I get home the battery stays full charge over night at least. Is there some thing in the alternator that could cause this problem but still charge the battery?

 

this might sound like a simple solve but have you had the battery tested ie the specific gravity.

as for testing for the battery drain. If doing it alone I have used a light tester and slowly pulled a fuse until the light goes of this will tell you where the power draw is ( you disconnect the negative terminal and used light tester as a jumper )

some of the other things to try are check the battery terminals for tight or corroded and check the negative cable to make sure you are getting a good ground if you are not the alternator will still show that it is charging proper but not into the battery.

 

Any of these sound familiar?

The battery drain was an issue on my 97, replaced the ignition switch problem gone!

"Issue: No start, cranks but no fire, No power to fuel pump or relay, No dash lights(start up dummy lights), unable to shift to neutral or move shifter, Battery dies weekly(3-7 days).
Resolution: Replace the Ignition switch module"

 

I have a 2000 blazer 4x4
battery is from 12/12

after 24hr of no use not enough power to start the truck, but the lights in the cabin worked.

I used a test light on the inside fuse box, the ones that light up a wrote down in a list. Then i went back and checked with a DVM.

The list.

2. 0
7. 0
8. .9
13. 0
14. 0
19. .9

fuse #/ results with DVM set to 200mV

Where do i need to go from here?

 

i was wondering if ever resoved the problem. mine is doing the same thing. thx