electrical help needed

[framedoctor]

Below is a pic of the hi/low switch? I believe.

[framedoctor]

Hopefully higher res on this one.

[Canoe]

Yes with the stereo and harness out it still buzzes

> With the stereo & harness still out, have you put that switch back in? Does it buzz, off? On?

[Canoe]

Below is a pic of the hi/low switch? I believe.

Looks like the right spot on the column, and it's got three terminals on the connector, and it's got a rod coming in from the right. ~edit:But, it's not like the one's on my Eagles; no fasteners to adjust it up/down the column to adjust the lever-to-switch input.
Does the lever feel & sound like it's switching?
Connector out, is there continuity between pins? Does that change when the lever switches it?

Additionally, you can test the connector (which is really testing the rest of the headlight circuit, as this bypasses the hi/lo switch). Do this wrong, and you could do damage. With the connector out, and the light switch off, (and if you've any doubts, with the battery disconnected), put a jumper wire between
framedoctor's continuity is different from what I remember
the middle connector slot and another slot. Jump the centre to one slot should give you low beams; centre jumped to the slot on the other side of the centre slot should give you low & high beams.
two of the pins will give you low beams; another two pins give you low & high beams.

I've used part of a thick paperclip for the jumper. The jumper sticking out is LIVE when you turn the light switch on, so you HAVE to ensure it cannot touch anything else. It is worth taping this to ensure that can't happen.
(This is also a work around to get headlights when the low/high switch burns out, while you chase down a replacement switch.)

[Canoe]

Hopefully higher res on this one.

Well, this one is 777x338.
The first one was 819x425.
So, no, not any more resolution/detail.
If you'd like, just email me the original from the phone. I can constrain it to 4000x and strip the EXIF out and post it.

Related,

... How are those wires joined under that electrical tape? ...

[Canoe]

... But, it's not like the one's on my Eagles; no fasteners to adjust it up/down the column to adjust the lever-to-switch input. ...

Just a different switch construction. Adjusts just the same. The lower fastner is visible in your image. The higher fastner is hidden to the right. (I had to look at the parts catalog in the Eaglepedia before that twigged.)

[framedoctor]

I checked the high low switch for continuity and I have continuity from the top pin to the bottom left and then after switching the high low the continuity switches to the other pin

[framedoctor]

I was also able to locate the ground for the rear defrost and it was indeed near the ribbon. I cleaned it up and reattached, however it did not change my gauge problem.

[Canoe]

So you're still testing with power for your guage problem, which is still present, but you don't mention if the headlight issue is still present.

have you redone the body ground yet?
https://forums.amceaglesden.com/index.php?topic=46908.msg362234#msg362234

Before the battery is connected, the ground to the car's body under the hood should be disconnected, cleaned and re-established to remove this common fault point from the situation. Do not skip this if the connection looks good; a number of cars that appeared to have a good ground connection had hidden corrosion (use dielectric grease to reduce this risk), that once cleaned and reconnected, returned the car to operating normally. If that cable/wire/strap's wires are corroded badly, that should be replaced as it may not be able to properly handle the required current or may be degraded enough that it's acting as a resistor. A replacement should be a sealed cable, like battery ground cables, so the wires are protected from corrosion.

[framedoctor]

I have the ground strap to redo. The ground on the firewall for cluster was redone, I added ground from negative battery to body, and the defroster ground redone. Headlights still do not come on and headlights and blower still make gauges wacky.

[Mitch]

There's a ground point on the firewall, in the engine bay, between the brake booster and the back of the engine valve cover, that caused me some grief on my '87 sedan years ago. (I forget what the symptoms were but they were wonky.) You'll see one or more small black wires grounded there. It may not be your culprit but it wouldn't hurt to refresh the point.

[framedoctor]

Mitch, I did find that one after reading your original post about it I think, I did refresh it with fingers crossed to no avail. Thank you though.

[framedoctor]

close image of stereo harness damage

[Canoe]

We've been doing some gathering and thinking offline through emails.

Attached are photos of:

• the modified stereo harness
• closeup of its splices with electrical tape unwrapped
• Defroster switch connector

Seen:

• Above the harness splices, the new stereo black ground wire shows a cut & break fault in the insulation.
• The old ground wire below the splice did not melt.
• The new ground wire from the splice to that fault did not melt. Its portion closest to the ferrule shows some heat damage to the insulation from solder wicking up the wire, but the insulation beyond that to the fault is in good condition, with little if any melting of the crispness of the cut & break fault.
• Melting damage is from high current flow in the new ground wire from that fault along to the new stereo connector.
• Framedoctor's examination of the harness makes him believe that it was that ground wire that provided the heat that melted the other wires, due to their proximity.

- It appears that the current that melted that ground wire insulation either entered or exited at that fault, and either flowed to or from the ground pin in the new stereo connector.
- Burning smell occured when the Defroster was switched on. There was current somehow shorted into that harness ground wire from the Defroster switch on/off|timing circuit board, its switched output to the defroster or that switched path's related connector or harness.
- From the lack of melting in the old harness ground wire and the short portion with no heat damage in the new harness ground wire from the fault towards the splice:

• no shorting current flowed down the old harness ground wire into the vehicle harness (implying a fault in that ground path that existed prior to turning on defrosting), or
• that flow was of very short duration and caused a fault in that ground path (fuse on ground to protect the harness and/or prevent fire?), ending shorting current flow in that direction. (Given the change in the headlight & gauge behaviour pre-/post-melting, I think this is highly likely.)

Which means that all or the bulk of the high current short ended up entering the melted portion of the ground wire, either:

• (mostly likely) at that fault and flowed to the new stereo connector's ground pin (and likely grounded to the new stereo chassis, hence through its mounting to vehicle ground)
  (it may have temporarily (also) flowed down the stereo harness into the vehicle harness, damaging that path to ground, leaving shorting current to flow the other direction to the new stereo, its chassis, to vehicle ground), or alternately
• (possibly? this would be a real stretch...) the short somehow ended up at the new stereo's chassis, but the chassis didn't have a path to ground, leaving current to flow out the stereo connector and down its ground wire to that fault which had contact with something providing a path to ground.
  (The vehicle harness's path to ground may have been degraded or damaged (pre-existing or from initial shorting current flow), leaving the fault with a ground path as a better or only path to ground.)

The Defroster switch connector has four connecting tabs, each with a different colour.

• Black: negative|ground
• Red: + 12 VDC
• Brown (behind blue in photo): switched with ACC, +12 VDC Vacc
• Blue: must be the switched output (note exposed conductor, and what looks like remelted solder on the switch circuilt board in an earlier photo)

The switched output goes to two blue wires. One obviously to the rear hatch window's defroster ribbon & wires. Does anyone know where the other defroster wire would be going on this '88 wagon?

Framedoctor is exploring the new stereo, its mounting box, the stereo harness and the Defroster switch for clues as to what that fault in the harness ground wire could have reached.

Framedoctor has added a battery cable from the battery negative terminal to the vehicle body for a vehicle ground. He's also replaced the ground strap from the block to the vehicle body with a battery cable with sealed cable ends, so they can't corrode in the future.

(server is refusing the three photos, each under the specified size; will load them one per post)

[Canoe]

stereo harness split & fault

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