95 Geo wiring issues

[Torqued]

Hi, for all of you that have been having weird electrical problems with your Metro, here's what I've found:
I've had some headlight issues for the last couple of months and I've traced it down to the wiring harness just forward of the firewall on the drivers side. I had one dim headlight that would work intermittently for a while and it turned out to be corrosion in the harness. Just forward of the firewall on the drivers side the harness that comes through the firewall from the fuse panel makes a small dip as it goes forward. It seems that moisture collects inside the tape wrapped harness and corrodes the wires where the harness dips to it's low point. There are a couple of splices there for the headlights and wires corroded in two was the cause of my problems but I can see where it could be an issue for other things as well.
Just a note of information for those of you ready to pound your heads against a wall.

Torqued

[carpenter_jai]

Thanks for that tip. This comes just in time for me to better fix my dim headlight troubles before the long highway trip season opens. If I come up with anything good, I'll be sure to put up some pictures.

Jai

[91Caprice9c1]

This has been a common problem for me. I've had to cut out and re-splice this connection on a few cars in the fleet. Definitely a good heads up, and something that seems will inevitably come up for Metro owners.

-MechanicMatt

[matt1212]

my ptc fuse will blow every time I start the engine anyone know why

[GM Line Rat]

I had this same problem on my 94 2-Dr Metro (RIP). I too had to "Cut out / resplice" in new wires for the headlights in this same area of the harness....But once I discovered the cause of it, I zip tied the harness tight after the repair, then coated the whole harness area where the failure was with clear GE Silicone caulk to seal out any moisture in the future. Let it dry completly overnight, then re-taped the harness up.........Done! Haven't had this issue yet with my 94 4-Dr Metro, but I'm not going to wait for a failure, now that this thread was brought the issue back up again!

Originally Posted by matt1212

my ptc fuse will blow every time I start the engine anyone know why

PTC ??? Be more specific please!

[matt1212]

ptc in the fuse block under the hood its just labled ptc I have no idea what it does car runs fine without it and all lights accories work so right now im running without fuse in I just bought this car so i dont have a service manual yet got one ordered get it next week

[91Caprice9c1]

The PTC fuse controls the EFE relay.

Labeled "1", the EFE heater warms the air/fuel charge coming from the throttle body, and aids 'cold start' efficiency. It is not a vital component, but may set a check engine light.



-MechanicMatt

[matt1212]

thank you for the information. what would cause the fuse to blow a bad wire or the efe heater itself need replaced?looked up efe relay its a four prong relay could relay cause the 30 amp fuse to blow? only code I get is 51 egr, before I changed egr I was getting throttle pos senssor code but now only 51, how long can you run before your valves burn with a clogged port on intake manifold I have only drove car 600 miles since I bought it but have no idea how long its been plugged the guy I bought car from said top of motor was rebuilt 10,000 miles ago so assuming its been plugged 10,600 miles would the valves be ok I plan on removing intake manifold to clean ports this week

[91Caprice9c1]

Yeah. Bad wiring, the heater itself or a bad relay can all cause the fuse to blow. Then again, sometimes fuses blow as a result of rare, transient voltage spikes. The most common cause is a short to ground, which you can test by installing an ohm meter between the power side of the circuit and chassis ground. Perform this test with the heater disconnected. Any reading other than Overload (OL) indicates a short.

How long can you go with an in-op EGR? I couldn't tell ya. Depends on the type of driving you do, and how extreme the blockage is. You can test the health of your valves with a compression test. This is something you should tend to as promptly as possible.

-MechanicMatt

[matt1212]

thanks for the input