Truck dies after removing instrument cluster?! wtf?

[KevinL1987]

I need some help. While chasing down a short that would cause my Illum fuse to pop as soon as I turned on my parking lights, I removed my gauge cluster so I can run a couple remote wires to the switch bank.

I had the truck running when I pulled the cluster, and I noticed that everything got dim, and the heater almost stopped blowing, so I re-insterted the cluster and it came back alive. My charge started going back up, and everything got bright again.


Is this normal on GMT400's?

 

[df2x4]

I'm honestly not sure, but common sense tells me that pulling the cluster on a running vehicle probably isn't a good idea. I'm pretty sure there was a thread the other day posted by someone who fried some things by doing this.

 

[KevinL1987]

I'm honestly not sure, but common sense tells me that pulling the cluster on a running vehicle probably isn't a good idea. I'm pretty sure there was a thread the other day posted by someone who fried some things by doing this.

Yeah, I know that it isn't best to do so. I tend to push my luck at times, I've done it several times with no bad outcome.
If you can link that thread, I'd love to give it a read.


But, what stumps me is, does my cluster control my alternator charge? It's weird that it would cause the truck to stop charging, and to die as I was pretty sure there isn't a BCM in a 97. I could be wrong though.

 

[someotherguy]

Alternator quits charging because warning light no longer in circuit.

Put the cluster back in. Get a micro-fuse style circuit breaker of the correct voltage and replace the fuse with it. I'd probably start by temporarily disconnecting the taillight harness and isolate that, then alternately pull the front light harness (plug on 95-up is right there in the general area of the driver's fenderwell.) Then pull the bulbs that would come on with the park lamps and put them back in one by one until you trip the breaker. Sounds like a lot of work but it really isn't. Most likely a bulb that burned out and shorted. Kinda rare but it happens.

Richard

 

[KevinL1987]

Alternator quits charging because warning light no longer in circuit.

Put the cluster back in. Get a micro-fuse style circuit breaker of the correct voltage and replace the fuse with it. I'd probably start by temporarily disconnecting the taillight harness and isolate that, then alternately pull the front light harness (plug on 95-up is right there in the general area of the driver's fenderwell.) Then pull the bulbs that would come on with the park lamps and put them back in one by one until you trip the breaker. Sounds like a lot of work but it really isn't. Most likely a bulb that burned out and shorted. Kinda rare but it happens.

Richard

Richard, Thanks a ton for letting me know that. I would have never guessed that, that would cause the alt to stop charging!

I found the issue about 20 minutes ago. Seems as if my Sony Headunit (CDX-GT25MPW) doesn't have an illumination wire. Whomever wired the headunit up, did not correctly cap the wire coming from the harness.
I've never had an issue with this until yesterday. I pulled the harness out, and removed the illum wire. Soldered every connection and heat-shrunk the connection. Put the headunit back in, and a new fuse in the fusebox, and no issues!

 

[someotherguy]

That's nutty. Glad you found it so quickly. It's a reteaching of the old lesson, "suspect previous work."

Richard

 

[superdave]

Previous owner wiring can always be a fun filled event. I always try to solder and heat shrink wrap any connection. On stereo wires not used, I'll slip a piece of heat shrink tube over the wire and fold the end back into it. Hit it with the heat, and it's under controll. I will occasionally use a crimp connector when I just can't access the spot with a soldering iron/gun. Of course, I am the **** retentive mechanic.

 

[df2x4]

If you can link that thread, I'd love to give it a read.

Not much reading really, but here it is. Took me a while to find it as it was posted in the Engine section for some reason.

http://www.gmt400.com/forum/showthread.php?27555-No-speedometer-or-coolant-temp-gauge

Glad you got it figured out!

 

[KevinL1987]

That's nutty. Glad you found it so quickly. It's a reteaching of the old lesson, "suspect previous work."

Richard

Indeed. Always go for what your gut tells you that could be wrong. I've faced this several times in the past.

Previous owner wiring can always be a fun filled event. I always try to solder and heat shrink wrap any connection. On stereo wires not used, I'll slip a piece of heat shrink tube over the wire and fold the end back into it. Hit it with the heat, and it's under controll. I will occasionally use a crimp connector when I just can't access the spot with a soldering iron/gun. Of course, I am the **** retentive mechanic.

I know what you mean. I'm **** about wiring myself. Currently reworking my headlight harness, which I may make a few kits to sell depending on how pleased I am with mine. Will be doing a fog harness next.

Not much reading really, but here it is. Took me a while to find it as it was posted in the Engine section for some reason.

http://www.gmt400.com/forum/showthread.php?27555-No-speedometer-or-coolant-temp-gauge

Glad you got it figured out!

Thanks for the link brother. Sometimes it's the simple stuff that people overlook.