Wankenstein

1997 Civic EX Coupe. Stock. A/T. 165K miles

Driver side low beam headlight not working. Replaced both high and low beam fuses (under dash). Replaced with new H4/9003 bulb yesterday. Cleaned all three terminal contact points (as best as possible.. dialectric grease). Check with voltmeter today by attaching negative probe to chassis ground and using positive probe to check each of the three terminals... DMM set to 20v DC. Lights set to low beam.

Terminal readings:

.25 ---

0--- .04 ---

Forgot to try on high beam setting but, high beam is working. Harness issue? Possible frayed wire? Will lead to deeper car maintanence depression?..lol

ezone

Turn headlights on, low beam.
Voltmeter: Stab the tip onto the test tab on top of the fuses, both sides, fuse 21 and 22 in the DASH fuse box.

You are familiar with the test tabs on top of the fuses, yes?

Are both fuses powered up (B+), both sides of both fuses?



Next wiring junction is a 10 wire blue shell connector next to and slightly below the brake master cylinder. Inspect wiring and connections there, and follow that harness from the firewall toward the front looking for any signs of damage (rodent chews).

ezone

Low beams ON
If you can backprobe, test the red/yellow wire on the front side of the connector for power. IF you got power there, then the wiring is probably open between that point and the bulb socket. You just gotta find it.

If you can't backprobe, Take apart that connector, test the firewall side of the connector for B+ on....left low beam should be a red/yellow wire. Then ohm test the mate (still red/yellow) between the forward half of that connector and the headlight socket.


If your fuses had power but you didn't have power on the firewall side of that blue connector, you're probably gonna be digging into the wiring coming from the dash fusebox.

Wankenstein

I think I'm losing it. Now the low beams are working on both sides but, the driver's side high beam and blue high beam dash indicator light is not working.
The blue indicator light and both left and right high beams were working when I initially posted this thread.

Is there a dash fuse for the blue high beam indicator light?

ezone

Huh....


Fuse 4, right (passengers) high beam
Fuse 5, left (drivers) high beam AND dash indicator
21, right low beam
22, left low beam

I'm still waiting for you to tell me if the corresponding fuses are powered up or not, when the (whichever) headlight does not work.
Important info here.
If you lost the indicator, I think fuse 5 isn't powered or it's lost connection to two different harness outputs


Got water leaks or damage inside the car?
If you're randomly losing power to the headlight fuses, I think I might then check that all harness connectors are securely connected into front and back of the dash fusebox, twist, wiggle, stress, wiggle the fuses in (and maybe kick) the fusebox and see if anything changes. Have someone watching out front so they can yell if anything happens.

Wankenstein

http://troubleshootmyvehicle.com/hon...-dash-fuse-box

I had sixty hour work week this week and no energy when I did have the time. I should have time and energy tomorrow... today is a 14 hour shift though.

So, it may not be surprising if fuse #5 isn't powered?
The headlight issue started soon after I used silicone caulking on the front left torque mount so, it's possible the increased vibrations may have jarred a connection loose or caused a break in the wiring.


There isn't any noticeable interior leaks other than one in the trunk's drain channel on passenger side. My son can watch the headlights and I'll twist and wiggle the wires near the dash fuse panel.

ezone

Not just the wires, twist the entire fusebox.

Wankenstein

Wankenstein

Low beam on driver's side out now. Someone on HT confirmed your suggestion to twist the wires/fuse panel.

(copied and pasted): "Both high and low beams have separate circuits left and right high beam and left and right low beam and fuses for all 4 of them.I would confirm power at the left high beam fuse, [both test tips], if you have power at bot test tips on the left high beam fuse the problem must be between the fuse and the bulb socket so test at the socket, and because the high beam indicator is also a problem I would suspect the lug on the fuse box that has the head light wiring, and indicator lead in it to be the problem or the fuse box itself, you will need to test for power starting at the fuse box to see where to open circuit is."

I don't why I haven't got around to trying your suggestion yet but, I plan too very soon.

Update: Just twisted wires and fuse panel and no change. Jiggled driver's side light socket and low beam working again but, high beam is not. Recently, while low beam was out the bright's blue dash light would come on when brights selected. After getting the low beam working again blue dash light does not come on when brights are selected.

Wankenstein

Turns out for the low beam driverside it's a faulty wire near socket. I zip tied it up and that seems to be working well for now. If I eventually replace the faulty section should I snag some wire at a junkyard or would 22g stranded wire work well?

I have some teflon coated 22g stranded 1000v military spec wiring I use in guitar tube amps. Not sure if the resistance would be an issue but, at such a short length wouldn't think it would be.

ezone

22ga is probably too small for the amp load. What ga. is the original wire, 16-18 ?

Decent parts stores should be able to get you headlight bulb pigtails that you can splice onto your harness, just need to know what bulb type it needs to fit

Wankenstein

The faulty wire (one of four) seems to be at the harness area just before it turns toward toward headlight and splits into just three wires. The wires are not a solid color or as large in diameter as the ones shown in the pics you posted. Wires are each multicolored similar to the stock speaker wires used for 6th gen EX's.