electrical and ignition When will I ever learn

[carpediem]

About a month ago I noticed my lights weren't working.  I hardly ever drive my '72 tii at night, but I didn't think it would be hard to fix.  First I suspected the light switch itself.  I pulled the instrument cluster and then the switch, but it was fine.  Then I suspected the dimmer switch.  I removed the steering wheel and all the steering column trim so I could get the dimmer out.  It was fine.  Running out of options, I removed the front grill and one of the H4 headlight assemblies.  The bulb was fine and I had 12V at the connector.  Duh!  Bad ground!!  

 

My bad.  I started at the wrong end.  Instead of tearing apart the dash and switches, I should have started at the headlight end.  The fix was simple and obvious.  A PO had used an undersize screw to secure the ground harness to the chassis under the voltage regulator (my battery is in the trunk).  It eventually corroded and worked loose.  

 

Always check the grounds first.  I'm writing that on my blackboard 100 times...

 

[halboyles]

Seize the day and secure the ground.

 

The first corrective measure I perform on any running '02 I work on is to redo all the ground points.  In the engine bay, under the dash, and in the trunk.  If the electric fuel pump is grounded in the trunk it is especially important to check that one. Being stranded on the side of US 105 in LA at night with 4 lanes of cars whizzing by at warp speed changed my grounding religion.

 

Not to mention, it makes troubleshooting electrical issues so much easier.

[xferboy]

I had similar.  I knew all my external marker lights (and head lights) were working, but never looked at dash lights.

 

One day I actually had to drive after dark.  I had no dash lights.  Reaching under the dash while driving (no underdash pieces installed currently) I was able to massage the wires leading to the cluster enough to get dash lights for the drive home. 

 

Adjusting the connectors for the dash (I'm leaning to the ground) will be on a list for winter.

[Mike Self]

Even before you check grounds for non functoning electrical stuff...check the fuses.  

 

Not only do the fuses and their spring clips corrode, but the fuses themselves wear out. The fuse metal is much softer than those brass spring clips, and the clips wear holes in the fuses from the car's vibration.  So just wiggling the fuse in its holder may not make a good contact.  Pull the fuse out and carefully examine each end.  

 

There's a reason why no manufacturer uses these fuses any more.  And as an aside, Buss (US fuse manufacturer) at least used to make glass cartridge fuses with pointy ends to replace the ceramic Euro style fuses.  They don't corrode or wear out--but of course don't look stock under the fuse box cover.  Anyone know if they're still available?

 

mike