North American Turbocoupe Organization

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I have a 1988 turbo coupe with a manual trans and have recently had the instrument cluster out. After putting it back in, when I start the car there is a constant buzzing sound and the speedometer and tach won't work. It immediately pops fuse 18. When I took the cluster out, I noticed that coming out of pin 7 on the main harness, it has two wires coming out of it, a gray/yellow wire and a black wire, which the black wire is not attached to anything. I can not find a broken wire under the dash, so is this wire suppose to be attached to anything? Please help. I've done many hours of research, and found a couple topics like this, but the answer doesn't seem to be in the threads, they kind of just end without what was actually wrong.
Update: Changed ignition switch and connector because it was melted. Multi-switch connector also melted, but received wrong plug so going to re-order one today. Still same problem after putting in new parts. If anyone has some answers/suggestions please help. Going to local salvage yard tomorrow to get an instrument cluster to see if that is the problem.
I sent you a PM about schematics I can email
I will take all the help I can get. Thanks. On a good note, replacing melted connector/pigtail on multi-function switch fixed fog lights. If anyone needs this connector, all the ones part stores can get has one of the plugs turned the wrong way, so I had to get mine at a salvage yard. Just in case anyone has the same problem. Part store one is green, the one I needed was brown.
What kind of buzzing is it? It is loud and coming from the buzzer or from something else?
It was coming from the over boost buzzer. I unplugged it and the tach and speedo started working. After I put everything back together, they stopped working again. I left buzzer unplugged. I'm taking it to my local ford dealership Wednesday to see if they can diagnose it.
Forget the Ford dealer. Unless there is an old master mechanic there, no one at a dealer has seen a TC in 20+ years, and they likely dont have any manuals any more.
oops... nevermind... I see you already replaced the ignition switch.
I've got the exact same problem (among other electrical gremlins in the cooling fan system) so if anyone could figure it out, that'd be fantastic. Also, where could I find a copy of the instrument wiring diagram?
(04-05-2013, 09:47 PM)blchill Wrote: [ -> ]I will take all the help I can get.  Thanks.  On a good note, replacing melted connector/pigtail on multi-function switch fixed fog lights.  If anyone needs this connector, all the ones part stores can get has one of the plugs turned the wrong way, so I had to get mine at a salvage yard. Just in case anyone has the same problem.  Part store one is green, the one I needed was brown.

The Tech Article on Fog Light Modification is missing—I found this instead, which is the same article by Jeff K, just cut-and pasted into a message.

Convert your system to it. You won’t believe the difference it makes.

Briefly: the fog lamps require 30 amps to operate. They run through the same circuit as the A/C and a few other high-current items on the ignition switch. This current draw is too much for the switch and connector, which is why it fails and the connector is melted. Jeff K wrote the fog lamp mod to correct this. It adds a relay to the circuit—this allows much smaller voltage to power on the relay, which now carries the 30 amp current. No more high current draw on the ignition switch!

Before I made this change in late 2015 I was going through an ignition switch and connector every other year. Recently I had the switch apart to try and determine an unrelated starter issue and I was VERY pleasantly surprised to find NO damage to either the switch or the connector (It was so bad that I was carrying around a spare switch and connector so I could fix it “on the road”).

A source I have for the switch connector is Advance Auto Parts. The last time I replaced both I found the OEM connector was no longer available at any of the “usual” auto parts chains (forget Ford!). The difference is that the standard Ford connector is a 9 pin, whilst the one for the TC is 11, for two extra accessories apparently not found with the standard Ford unit.

The part # you will need is PT5534–in 2015 these were $3.35 each. I purchased 6, which ironically I don’t need all those now that I have fixed the issue.
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