John Struthers

Well,
My long running battle with the left side marker tailight was finally cured when I discovered that the paint shop who replaced the left rearquarter panel -hit and run last spring-
apparently ripped the rear lights out rather than remove the rear valance -first-. Then for reassembly they used 1 to three inch long sheetrock screws thru the light assembly to the upper and lower lips on the valance to hold things in place. Eventually, one of the -short- screws scuffed thru several wires. Tail light and brake light being among them. When the park, running lights, or, headlights were on and the brakes applied I guess the voltage, watt, amp spike was enough to smoke the fuse. I cut stripped, soldered, and used heat shrink tubing.
That cured the primary fault warning on the dash and the master caution warn light -after disconnect and reconnect of Battery-. Shortly thereafter, I got the master caution and brake pressure dash warning. New pads, new sensors -yep, checked before and after installation- bled the brakes, no leaks, no pulling, back in July.
Replaced a master cylinder brake sensor unhooked the batt. to clear fault and all was cool for awhile. Then the brake pressure warn appeared again. Checked fluid level, looked for seepage and leaks, bled the system, checked the pads -almost 100%- and retested pad sensors . All O.K.. Dennis Wilson recommended that I change the other master cylinder sensor - mine has 2 on the bottom of the MC. He believes that they should be replaced at the same time as this system is looking for balance/comparison as an additional duty.
Thinking about it... I think he is right.
The fault cleared then returned - intermittantly.
When I would disconnect batt. for tinkering or trickle charge the fault would clear for days then return.
I finally, removed both MC sensors and tapped them -upside down-. After re installation and hooking up the battery fault cleared for months.
The evening before last, I had given Pattycakes her weekly waxing, taken some 35mm flicks of her and was taking her on a sunset cruise.
Touched the brakes at a light and there was that tail light warn and master caution warn, yet again!
Finished the ride before dusk and while parking put her in reverse now the darn brake pressure warn AND pad warn joined in! <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />
In addition to aforementioned stuff the only electical glitches were the window switches, replaced, and swapped the lamp control unit.
About 2 weeks ago the mirror switch and sunroof switch got balky and my driver door -red- marker light went out. Last week the driver door glass developed a slow to close issue - only if below 30 degrees (?). Finally, with every thing off the ammeter reads a high 13, with parking light and or headlights on runs around 13 even. However, if I put on the brakes a nosedive to a low 11 to 10 range.
Anyone have an Idea? WAGS welcome for investigative purposes.
I'm ready to swap out the harness from dash to rear if necessary.
BTW Cleaned up every ground I could find to include; Battery, alt., multiple ground above/in fuse box, two frame/chassis straps up front, coil ground, even front and rear speaker grounds, radio/CD chassis ground, lighter, ashtray light, and all interior, underhood, and exterior light socket and ground connections. The brakes have solid pedal with no leak down.
I'm flat bambozzeled on this one. TIA
John S. 82' Weissach, Auto,. 'Pattycakes'

Old & New

John,

I'd probably check voltages with a DVM in a few spots & don't implicitly trust your dash meter.

Doublecheck all bulb wattages & wiring around the rear of the car. Use a clamp-on ammeter to determine actual current draw (Radio Shack &lt;$50).

Troubleshoot by process of elimination; short the brake wear sensors at the rubber plugs where they connect. Be real fussy about making sure these connections are clean.

I'm not completely familiar with the 928 MC warning sensors, but I know that in another car I have, there was a problem with false alarms until the system was bled *correctly*. It had to do with the balance between front & rear systems, and a little piston that had to be centered properly in the MC.

Just a start... be systematic & thorough.

Greg86andahalf

John,

As far as the pad sensors go, clean each ground at the caliper. there is a ground wire coming from the round connectors for the pad sensor wires.

WAG- how good is your battery? If it's getting old, I would try a replacement or temp swap with a known good one.

Greg

Paul D

John -
You gotta be kiddin' me. You must be at your wits end by now. There were some good suggestions here. I would make sure the battery was in tip top shape like Greg said or get a new one. When making voltage measurements you should only use a hand held meter. The dash board meter is not nearly as accurate. Good luck!

V-Fib

John,
It gets below 30 degrees in Midland? Brrrrrrr! I tried both liquid and dry graphite to the doors. Don't know which one worked better or if it was the combination both. Doors swing very freely, and no squeaks. As for the electrical problems continuing, I feel for ya. Have you tried exorcism?

Anthony Tate
79/928 Silver Metallic

John Struthers

All,
Thanks but all of this has been tried-again-.
Anyone have knowlege of a parts car I can buy the rear harness from?
Hmmm ...might as well get a NEW one from the Big Three.
Thanks again.
John S. & Pattycakes.

Dennis Wilson

John,

Don't take the dash voltmeter as gospel. I use mine to make sure the brake lights are working, If if drops one volt, the brake lights are OK. The amount your volt meter drops is probably indicating another short in the wiring. Have you done a complete check for more sheetrock screws? Have you done your monthly twisting/cleaning/replacing of fuses?

Dennis

Dozman

John,

Wish you said something about 4 months ago. Don't buy one just yet. Give me till the weekend, so I can check my spare parts, I might still have the rear harness.

What do you want it to cover? What part of the car? Cabin? Taillights to Cabin???

John Struthers

Dennis,
The short screws were the problem as they must have just been fishing for an anchor point.
All the short ones did was enter the 'box', where all the wires live.
Then they used the long ones to reach the 'tab area and lip of the facia. They probably spent more time concealing the screws than they did replacing the fender. It was a great job of camouflage.
I checked the wires out by feel in both directions and used a 10 power magnifyer to scope them out. Unless there is a short in the bundle between the pass thru to the area in the 1/4 covers, I'm at a loss. If I have to pull the covers and carpet to check I might as well have a new/GOOd used replacement harness. As stated in an earlier post, I had at one time cornered the market on Euro fuses in the Permian Basin, but yeah I did check again. Replaced the fried one. wiggled the rest as well as the relays. The fuse has no problems in parking/running light mode, or, with headlights on. Only when I tap the brakes.
Doz,
I'm game...
Let me know what you get, how much ...
Looking for whatever is running from tailight forward, If I have to do a complete set so be it.
Just so I can put this glitch behind me.
John S. and Pattycakes

thanks. John S.