Using a test light in this fashion is not a conclussive test, you need to use a DVOM to check parasitic draw. When you disconnect the battery, the memories discharge, (PCM, RKE, radio, clock, etc). When you connect the test light in series, the memories are recharged through the filament in the test light. After the memories recharge, the amperage draw drops to less than 1200ma, (not enough to illuminate the test light).

 

Thanks Captain! Ok, is a DVOM a test meter? Whats the best way to use it to find a short? I'm pretty sure the short is after the fuse box, becaus it only blows after I turn the key to ON!! I have a test meter, but not the best at using it, so please give detailed instructions and what settings I need to be on when testing! Thanks again

 

Remove #4 fuse, ignition in off position. Attach DVOM probes to each of the #4 fuse sockets in the fuse panel. DVOM set to ohm position. DVOM should indicate a short circuit, (low resistance, close to zero).


Here is a list of what you need to unplug/disconnect, (one at a time) until the DVOM indicates an open circuit, (high resistance, infinite reading).

NOTE: Your vehicle may or may not be equipped with all of these items.

A/C relay (underhood left side of cowl)
Instrument cluster
Rear defogger switch
"W" engine intake manifold runner control valve, (top of plenum)
"W" engine oxygen sensor behind catalytic converter
"Z" engine oxygen sensor in crossover pipe
DRL module, (behind instrument panel left side)
DRL relay (in convenience center)
Auto transmission shift solenoid harness, (passenger side of trans)
Voltage regulator on alternator
Audio alarm, (chime) module, (in convenience center)

Post your results.

 

Thanks Captain for the detailed info! I'm not the sharpest tool in the shed, so here are some more questions!

Keep in mind, I have a 95 blazer LS 4.3 vortec 4x4.

What's the best ohms setting, 2000, 200, 20, or what?
I have 3 relays under the hood on the back firewall, which one is the A/C relay?
Not sure what you mean by COWL? (what's a cowl)
Instrument cluster, is that just one big plug out the back of the instrument panel?
DRL module, (left side is drivers side)???
DRL relay and chime module, (where is convenience center)??
If you have any pics of these locations that would be great too!!

Sorry for so many questions, I'm determined to find this short!!!
And you can be asured I'll post my results when I find it, so the next person won't have to go through what I have!!!!

 

Set the DVOM to the lowest resistance range, (20 ohms).
The AC relay has 4 wires: Pink, black, white, and dark blue.
Cowl is another word for firewall, (that's where the 3 relays are attached).
The electrical connector for the instrument cluster is part of the back of the cluster. When you remove the instrument cluster, it automatically disconnects. Pull it out, you'll understand
DRL module is behind/under the instrument panel, (dash) left, (driver) side.
The convenience center... could be behind the center console if equipped, might be under the hood, or it might be behind the glove box. The module has 8 terminals and 9 wires, (1 of the terminals has 2 wires).
Sorry, no pics available.

 

Do I need to pull out the whole instrument cluster just to disconect it, and how do I pull it out??? (is it easy??) What does the convenience center look like, is it a black box, does it say convenience center on it? I hope these questions don't sound dumb to you, but i've been told there are no dumb questions! lol

 

The connector for the cluster is built in to the back of the cluster. The other half of the connector is built into the instrument panel. When you remove the cluster, the connector unplugs. A few 7mm screws are all that hold the cluster in place.

Not certain on the location of the convenience center on 1995, but if I remember correctly, it's a black plastic box with relays etc inside. Possibly next to the battery??? Can't remember.

 

did you ever find the problem and fix it? I have the same issue. thx

 

Sorry I havn't been out here in a while, I've been sick ( CHRON'S DISEASE ) I still havn't found the problem, and I've search high and low!! One thing I've noticed is that the #5 fuse is shorting out too, but doesn't blow the fuse! Could that mean the fuse block itself is shorting out from #4 to #5????? Alphadog if you find the problem in your car, please let me know, and I'll do the same!!!!!

 

sorry to hear Schleprock. How do you know 5 was shorted without blowing a fuse? I have gone through disconnected everything on the list for fuse 4 except the instrument panel itself. Trying to get to that now. having trouble getting the trim out to get to the instrument panel. I have it loose. just cant seem to get it past the steering wheel. Afraid I am going to break it. Did you get yours out?