I finally got around to investigating a nagging battery draining issue I've had for a while. Using a test light approach I discovered that my "CTSY" (courtesy) fuse is the problem. My question is how do I pinpoint the issue beyond here? I've checked connections on the cigarette lighter and dome lights. Should I check the relays? If so does anyone know where they are located? As you can tell my wiring knowledge is limited. Any insight is appreciated.

Thanks in advance,

Justin
1989 20th Anniversary Turbo Trans AM

 

Hello Whtlightning,

Using a test light on the ACC fuse will show power there because it draws power from the battery and is always "HOT". To check for a battery drain, you need to use a ampmeter.

 

Here is the correct way to use the test light:
Remove one of the battery cables and connect a 12 volt "test light" between the battery and disconnected cable. Light will be ON of something is draining current from the battery. Make sure everything it turned off, including the interior lamps (close the doors), then pull one fuse at a time. If pulling a fuse makes the test light go dim, then you've found which circuit is draining your battery.

 

Hello Whtlightning,

Here is a procedure and chart for checking for a battery drain. One area mentioned in here is a drain caused by the ECM, and is sometimes overlooked.

 

page 2 Hope this helps you!!!!!!!

 

Thanks Trickster. I'll let you know what I find.

 

Trickster,

I followed the procedures outlined on the pages you sent me and the results are as follows. (all readings are quoted with multimeter on 10A setting)

All fuses in - 0.18
without ECM fuse - 0.18
without CTSY fuse - 0.02
After pulling the CTSY fuse and pulling the remainder of the fuses one at a time the reading never dropped below 0.02

To double check the ECM I used the ALDL voltage method outlined in the papers you sent me as well. With ignition in ON position the voltage was 5.01. In off position in was 0.00. Don't think it's the ECM.

As I mentioned in my first post I removed the CTSY fuse earlier (thinking I had identified the issue) and left the battery connected over night only to find the car dead as a doornail the next morning (below 4.0V).

Any other ideas. Could a fan relay gremlin be on the loose at night?

Thanks,
Justin

 

Hello Wtlightning,

Just one other question here, have you changed batteries at all during this time and have you had your alternator tested. If your battery has dropped down to 4 volts or less, it is sometimes difficult to get some batteries back up to par by charging them. Also, if I remember my electric scale correctly. A milliamp (ma) = 1/1000 of a amp, so if you have 0.18 amps with all fuses installed. That's 180 milliamps and when you pulled the ctsy fuse it dropped 160 milliamps. You definitely have a problem . Your ctsy fuse gets power directly from the battery and is linked to the tail fuse which goes to the light switch making the light switch hot at all times. Just for the heck of it, put the ctsy fuse back in and pull the tail fuse to see what your readings are. I'm sure you did it this way but, as you pulled each fuse and took a reading, did you put the fuse back in after you took the reading

 

Hello again Trickster,

I put the CTSY fuse back in and pulled the tail fuse. The drain stayed at 180mA. I then reverified the issue by pulling the CTSY fuse and it dropped back to 20mA. The door light switch was blocked during this test and I don't have a hood light.

The current battery in the car has only been recharged once(today) by a local interstate battery retailer. It was brand new when I pulled the CTSY fuse and let the car sit the other night. As soon as I got the new battery (under warranty from interstate) I immediately had the alternator tested. With a new battery and a good testing alternator I then decided to start the parasitic drain test mentioned in my first note. Thanks for sticking with me on this one.

Justin

 

One more thing. I just noticed an electrical clicking sound near the door switch when the test is done. Is this normal, could it be a short? I have that switch blocked in (closed) with a block of wood while testing.

 

Hello Whtlightning,

Here is a schematic of the accessories on the ctsy (ACC) fuse. Since it would seem that the drain is coming from that fuse, put the fuse back in (better yet, put a new fuse in) and pull each light or switch or relay in that circuit and see when the amperage drops. "NOTE": This schematic is for an 89 camaro but I think you will get the idea. That clicking sound could be your power door locks and they are in that circuit as are the power mirrors if you have them. Do you have a power antenna for your radio?

 

As I feared. I'll try to find some time this week to set aside for this little project. Will post back with findings. Thanks again.

 

So far I've tested the cigarette lighter, glove box light switch, power mirror switch, door jam switches, horn relay, hatch relase relay and power antennae relay. I also disconnected the power seats...I tinkered with these not too long ago and wanted to make sure.

All that is left are the door lock switches, map & dome lights and Delco-bose amplifier relay (Am I right to assume this is behind the radio?).

I beginning to think I have a short circuit somewhere. What's the best way to track this down? Also, how is the 20mA draw that I have with the CTSY fuse out enought to draw down the battery over night? I thought this amount of draw was typical for the radio clock and ECM.

 

try unplugging your radio.

I had a drain on the ACC fuse and it ended up being the radio. Before I replaced it with a new cd player I was getting a reading of about 0.26 amps drain with the car off. =)

 

No luck with the radio. I also pulled the plug on the map lights and removed the dome light bulb to no avail. I really doubt its the door locks and I'm not for sure if I have a Bose radio relay. At least it doesn't say Bose on the radio faceplate anywhere. Looking more and more like a short circuit. Is there an intellegient and cheap way to find a short?

 

ive got this same problem with th courtsy light fuse if i leave it in overnight battery will be dead in morning if i pull it it doesnt drain i never could find drain i ended up putting a toggle switch in so i could jus flip it instead of pulling fuse if you find your problem please let me know

 

Any other ideas?

 

Have you checked the power door locks and if so, what were the results. Here is a schematic of the power distribution for a 89 camaro and it should be fairly similar to yours. Note that the power cable for the ACC fuse also goes to the light switch circuit breaker, the ARC radio fuse in the convenience center and the fog lamp relay in the engine compartment.

 

I had a 2.8 that would suffer from low battery power sometimes even after a new battery and alternator. The battery would drain slowly and need to be recharged every month or so. I eventually replaced ther starter because it was slow to start the car. The problem went away after I put the new starter on. I think i had a drain from the old starter. I was just too lazy to replace it for a while because it still worked. Is your starter sluggish sometimes?

Other than that..... do you have a trunk light? I would maybe unplug all the lights and accesories and see if the problem goes away. If it goes away reconnect one accessory at a time every day or so and see what one was the culprit.

 

Thanks for everyone's help, especially Trickster. I'm getting closer, but not quite there yet.

Okay, I fixed one problem and caused another. I finally got pissed off and spend all night Saturday pulling every damn relay, switch, connection I could find...fog light relay, mass air flow relay, fuel pump relay, coolant fan relays, light switch connections, etc, etc... Anyway while tinkering around near the fuse box I discovered a non factory looking four prong spade relay connected to the fuse box and traveling back under the driver's side door sill where it was spliced into the fuel pump wiring harness in between the two back seats. Yes, I had to pull out the back seats and carpet to find the damn thing. Looks like one of the former owners tried a do-it-yourself hot wire the fuel pump job.

While tinkering around with this hack job I accidently blew a guage fuse. This is what happened. While driving around I put a load on the car by turing on the A/C. Right after I turned on the A/C the check engine light came on and the guages went dead.

I've replaced the guage fuse, but the check engine light stays on and the A/C compressor will not engage, no clicking sound. I've removed the hack hot wire job and crimped everything back nice and clean. Using a paperclip I get a code 32- EGR. I've had my heads ported and the EGR has always been blocked off, but the check engine light never came on before.

I got my hands on an 89 pontiac firebird service manual and on page 8A-64-0 it mentions a relationship between the "service engine soon" light and a diode inside the compressor connector. I pulled the compressor connector and the check engine light dosen't go away. I can't find a diode inside the connector.

Any ideas?

 

Hello again whtlightning,

The diode is a small one tucked down inside the front of the connector and the connector is wrapped in electrical tape. See picture. To clear the codes from the computer if you haven't already done so, you nead to disconnect the positive cable from the battery for about 5 minutes or so and then re-connect it. Ya gotta love those hack jobs.

 

Still don't see the diode. I've taken some pictures, but they are too big to post. Can you PM me your email?

Thanks

 

It's the one in my profile.

 

I've established my A/C compressor clutch diode is MIA. Someone suggested jumping the accumulator connector and high pressure cutoff switch. I've done both and the compressor still won't engage. With the check engine light staying on I beginning to think the ECM is damaged. The car runs, but it seems to run a little rougher than I remember. Any other ideas?

 

With the engine on and the setting on max or normal A/C I don't get a voltage reading from either the A/C compressor clutch or the high pressure cutoff switch when I ground out either of the two female terminals on each connector. My next thought was to jump the male terminals on the actual compressor clutch straight to the positive battery terminal. The compressor clutch didn't engage using this method either.

I'm flying blind here, anyone have any other ideas? It's getting quite toasty here in Houston.

 

Most of the cars I have seen have the diode thingie hanging outside of the plastic. You should see it if you take the tape off. I have several extra wiresets from various f-bodys and I can see the diode thing on all of them. What I would do is find one off a junk car and cut off the conector from one that has it and solder it to your wires. I dont know if this would make the air work though, but you would take care of the diode thingie.

 

After additional testing I discovered I have two problems. Damaged ECM and damaged clutch coil within my compressor clutch. I replaced the ECM and my check engine light is now finally off. Apparently the A/C pin within the ECM was damaged. The bigger problem is the damaged A/C clutch coil. Can I replace the clutch without losing my R12 charge? The local A/C shop told me to replace the entire compressor, but I know this requires recharging the entire system and R12 isn't cheap.

 

jester, where are you getting those schematics, and are they in color? i've found the links to the 85 and 86 camaro wiring in the tech article section, but i really need wiring diagrams for an 82 Trans Am. the stuff I'm messing with is different (lights, and rear defroster, namely). knowing where to find these awesome full color diagrams would be a huge help. is it on the internet somewhere? a dealer item? a manual of some kind? any help would be great.

 

Some of the manuals have full color schematics in them (usually it's the earlier ones) and others don't. You can find the manuals at Helms inc or sometimes on E-bay.

 

so they're out of helms manuals? makes sense. so try to find an earlier helms manual for color schematics..... check. thanks.

 

Finally got my A/C fixed. Apparently the high side pressure switch in the back of the compressor was damaged from the shock and wasn't grounding. Apparently running battery voltage directly to the clutch connector doesn't work if the high pressure switch isn't grounded. Anyway, to replace the switch you have to go in through the back of the compressor and disconnect your lines which for me meant losing my R12 charge. I had a local shop do the work including new orfice, o-rings, switch, diode, R134 charge, etc for $350.00. BTW, I discovered during my search you can't find a clutch coil only for a turbo V6, you have to buy an entire unit just for the coil.

I would like to thank everyone for their reply's, especially Trickster. Unbelievable patience, :hail:

FYI, I got my non-color service manual on ebay.