Instrument Cluster Blackout?

[Dnny44]

Hey guys, kind of new to the forum, but I've been around trying to find an answer for this problem I'm having on my 04 expy.

Completely Randomly, the instrument cluster, radio, and power windows stop working. Unless, one is to repetitively bang on the top of the dash above the instrument cluster then it may or may not come back on for any amount of time.

I know this has been a problem on a lot of 1st gens but haven't found any solutions for 2nd gens. I know that it is at least blowing fuse 1 (10 A) but still need to see what others have been effected. I'm trying to see if anyone has any ideas on what solder joints may need to be fixed on the cluster because they are very different from the 2000 model shown on most forums.

Any help is greatly appreciated. If a picture of the circuit board would help I will be glad to get one I just haven't been able to find a diagram to try and trace the issue.

 

[stamp11127]

Need to know which fuse is blowing. The shop manual has the fuses labeled as F1.1, F1.2 and so on.

 

[Dnny44]

This is the diagram in the owner's manual, fuse #1 is that is being blown, I replaced it but something keeps blowing it.

 

[stamp11127]

How are you with troubleshooting electrical issues? Do you have and know how to use a DMM? Lastly, can you read wiring diagrams?

 

[Dnny44]

Yes I have a multimeter, and can read a wiring diagram; I'm an ECE student.

I however, do not have access to the shop manual so I can't look at the wiring diagrams and have had to manually trace everything with the multimeter. This however is hard because If the problem is not active when I trace the lines then it is easy to miss it.

 

[stamp11127]

Ok, you know the first two steps - source voltage and fuses. PM me an email address and I will send you the diagrams.
Check the grounds at the kick panels if they kept them in the same spot as the 1st gens.

 

[Dnny44]

I feel like I should also mention that just before the cluster, radio, and windows go out the voltmeter on the cluster begins to drop and the parking brake light comes on; as soon as the voltmeter bottoms out it all shuts off. Every once in a while the voltmeter will almost reach the bottom and then recover and everything remains on.

Also what is the best way to check the grounds on the fuse panel without pulling it out?
Thanks for the help Stamp

 

[stamp11127]

When checking any connection you always check for visual problems first- cut insulation, corrosion, broken wires etc. If nothing looks wrong then you can check for voltage drop on a connection, segment or segments.

 

[Dnny44]

Sorry guys had to make an unexpected trip to Louisiana. I will hopefully get to jump into testing the grounds Saturday afternoon

 

[Dnny44]

Hey guys, so sorry for the delay but it seems that after testing with the meter, that the grounds on the fuse box are working correctly. I have however noticed that if after you turn the truck on and then hold the key to the START position the speedo and tacho will sweep all the way to the right. The temp and oil gauges will also read normally but the voltmeter gauge will move up to only read 0. I was trying to figure out if something was misreading the voltage from the battery and trying to turn accessory power off to keep the truck running. Again thanks for the help Stamp, just curious what the next step would be.