No Interior Lights On the Testarossa

Check your fuse box for a 20 amp blown fuse. Mine was fourth from the left, I think, and the lights were not listed as part of the circuit.

 

Check the plunger type switch on the door frame.

 

Are you saying that you get nothing when opening either door or just the LH door?

 

Are your cigarette lighter, power door locks, and rear window heater working? (They use the same +12V power supplied by fuse #2 as the door and roof lights).

If not (and fuse #2 is OK), check the two RN (red/black) wires at one end of the "k" white connector (i.e., unplug the "k" connector and inspect/reseat) -- the two RN wires should always be +12V (even with the key "off"):
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If the RN wires are at +12V, then you are really only left with the door switches themselves as Dave suggested -- maybe someone repainted the door jambs and the switch bodies really aren't well grounded as they should be.

 

Just a thought, but all the door related lights come on through one choke point at the fuse box. They go through the 2nd from the left fuse (looking at the fuse box, really the right side of the car) which is removed in this pic. Then they leave on the very far right of the "K" connector, right by that burned out A/C pin in my pic. So assuming your fuse is OK, is it possible that either the K connector isn't seated correctly on the right side, or you too have a burned pin for the A/C as seen in this picture which has caused the pin for the door lights or even the PCB to fail?
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OK, so with that you have some indication that you're getting +12V power through connector K all the way through C9 to power the passenger door, and that at least some times your passenger door pin switch works and is connected through C9. Note that both the "puddle" (bottom door) light and "marker" (red) lights are connected at the door, so if the marker isn't working and the puddle light is I'd suspect it's just a bulb or the seating of the bulb.

Anyway, if you've got power at the door but not power to the dome/map lights, even when actuated manually using the buttons (is this correct or no?) then I'd say that you're not getting +12V through connector C8 (see picture #3 which is shot looking at the glove compartment emergency latch http://www.ferrarichat.com/forum/showpost.php?p=139319104&postcount=8). If the dome light buttons manually activate the lights but the passenger door switch does not then there's some sort of connection problem between C9 pin 9 and C8 pin 4 (see the purple [supposed to be black according to the manual] wires in pictures #2 and #3 in that post, and note that someone has tapped into one of the wires at some point for their own purposes, which may be a common issue, say for alarms).

I have never actually looked at the +12V power at C8, but it's supposed to be on pin 8, with two RN (red/black) wires coming in on the "car" side and one RN wire leaving towards the dome light according to the '88 US wiring diagrams (which are rarely right in my car). You can also check C8 pin 4 and see if you're getting signal from that passenger door; you should see +12V when the door is closed, and 0V when open. Another thing you can check is to simply ground out the passenger pin switch in case the switch is scratchy. Just take a wire from a good ground and clip it to the wire leading off the back of the switch (see pic #1). Note that it's the top switch for my '90 but the bottom switch for Shamile's '91, so you'll have to play with it to see which way it is on your car.

 

This confirms that you do have +12V power present at the RN wires in the k connectors. However, I just noticed that my TR's behavior doesn't match how the US schematic says it should work so not sure I can help much (although I do have an aftermarket alarm so it might have been mucked with ) The schematic says that when either door is open, the lights in both doors and the dome light should be "on". On my TR, the LH switch only controls the LH door lights, and the RH switch controls the RH door lights and the dome light. Can someone else with an unmodified US TR confirm/deny if their system works like the schematic says it should? I.e., open both doors -- all door lights and the dome light should be "on" -- manually depress one of the door light switch plungers (with the door still open so you can still see the door lights) -- do all the lights stay "on"?

For both the fog light switch window and the rear window heater switch, the indicator is in the switch itself -- the white logo is supposed to be translucent and light up when the switch is "on". On my TR, the white areas are almost opaque, so, unless you are in a totally dark environment, you can't see them "glowing". Since the manual switches for your dome and swivel lights aren't working, your rear window heater system might not be working either (they get power from the same place), but, if you sit in your TR in a totally dark garage, turn the key "on", and press the foglights switch "on", you might be able to see a change in the logo.

The manual switches for the dome and swivel light should work with everything else "off". The same RN wire supplies +12V power to these lights, but it passes thru more connectors (downstream of the k connector) to get there. When you turn the switches "on", this add a ground to turn "on" the corresponding light. IMO your only choice here is to get inside the overhead console and confirm/deny if +12V is present on the RN wire, if the bulbs are OK, if the switches are connected to ground on the other side, etc.

Good Hunting!

 

Shamile has confirmed this "all on" operation on his '91, though I'm not sure was have confirmation that it's unmodified:

http://www.ferrarichat.com/forum/showpost.php?p=139056262&postcount=13

My '90 looks to be unmodified and it does not agree with the '88 US wiring diagrams in that there is no connection to the dome light from C1, and therefore the action is exactly as you described. On the last pic here, C1 has only one violet/black (black in the manual) wire on the "car" side (left in the pic). I'm glad to get confirmation from someone else that this the way some of these cars are actually wired!

 

Hey Steve, I think I figured out why the car can't be wired like it says in the schematic, which may explain the deviation that I think you and I both see in our cars. I wired mine up with a bypass wire essentially to recreate the circuit path from C1 pin 9 to C8 pin 4 that's shown in the pre- and post-'88 US diagrams. But here's the problem: Instead of the light for the key switch that seems to be shown in the diagrams, the "other" wire from the driver's pin switch actually goes to my key buzzer, that warns you that the key is in the ignition but the door is open. So the result is that any illumination of the dome light, even using the manual switch at the light, will set off the buzzer. Just figured this one out because it happened to me, but reviewing the diagrams it makes sense. What do you think?

I'm not sure if their work around for this problem was simply to eliminate the function of the driver's side operating the dome light, or if there's some modification where they've got a diode in the circuit somewhere. I'm still damn curious about this, regardless of how useless the light is.

 

Yes, those are the tension motors for the shoulder belts.

IIRC, those two connector are for the pushbutton/lamp assembly that is mounted on the back of the center glovebox itself (i.e., the thing missing in your picture). When you open the top lid of the center glovebox, the plunger should pop up (completing the circuit) and the light should come "on" (if the exterior lights are "on") -- do you not have this pushbutton/lamp assembly on the back of your center glovebox.

 

First, let me say that the wire colors not matching disturbes me a lot (and puts up the flag of total uncertainty), but I think that you just might be using the wrong LH door switch to go to the dome light and the RH door lamps. As far as I can see, the whole reason for the two door switches doing the same thing on each side was to isolate the manual operation of the interior lamps from the seatbelt/key buzzer stuff. Can you try moving your added connection to the other LH door switch and see if you can get the "all on" operation of the door/dome lights without setting off the buzzer when manually turning "on" the dome light?

I'll try to have a look at my C1 connector and see what's there and what color wires (in the harness) are connected to the LH door lamp switch and the LH door seat belt switch.

 

Need to correct myself on both these points -- there is a green indicator lamp in the center console next to the oil temp gauge that should come "on" when the fog lights are "on", and there is an amber indicator lamp on the left side of instrument pod (under the emergency brake warning light) that should come "on" when the rear window heater is "on". (The symbol on the foglight switch itself should light up when the external lights are "on", but mine is nearly opaque so hard to detect).

 

James - Just had a close look at my C1 connector, and, like yours, there is only 1 ZN (purple/black) wire at pin 9 on the not-door side (not 2 black as shown in the 509/88 TR wiring diagram) -- so no connection to my dome light and the RH door lights either (and it didn't appear messed with). Seems odd that Shamile's '91 would have it, and my '91 wouldn't...

 

Yeah, the wire color and wiring discrepancies made me really question my identification, and it took a lot of circuit isolation and analysis of circuit functions to feel pretty confident of my identification in the other thread. I'd have to say that there are a lot of wrong color issues centered around connector C8, even leading back to the K connector, though I have yet to do any systematic research. But I would note that while the "car" side of C1, C9 and C8 have the wrong color, the other sides (to doors, dome light) seem to lead away in N/black as in the schematics. Also the other pin switches, for the seat belts (bottom on mine, top on Shamile's), are correctly MB and M.

We still have one unknown possible route to connect the driver's side door to the rest of the system: the second ZN/violet-black wire that leads away from the driver's door light pin switch (the other one leads to C1), that in the schematics is shown (as N) leading to the connector for the ignition switch "light" - a light I'm pretty sure I don't and can't have? Because my door-open/key-in buzzer is associated with the driver's side dome light pin switch (even before any mod by me) and not the seat belt pin switch, my conjecture is that wire somehow ends up running this buzzer (I still haven't hunted down either the buzzer or the unnamed ignition switch connector).

Also of note is that there IS a second Z/violet wire coming into C8 pin 4 towards the dome light, just as shown in the schematics (of course in N). The first Z wire has nice continuity to C9 pin 9 as it should, and the other connects to... who knows? Sure isn't C1 on either of our cars. It is Z and not ZN, so if nothing else there would have to be some intervening connection if that other ZN wire that leaves the driver's side pin switch were intended to make the connection.

And I don't want to put works in Shamile's mouth and still don't have confirmation from him that his is stock or that his connects through a split at C1, so who knows. Could be hacked in to work, though in my current hack, now with a diode to prevent unintended activation of the buzzer, the driver's side door lights are not activated by the other circuits. (I've got a PM in to Shamile to find out if his buzzer also works as mine did before the diode fix).

Thanks for the confirmation of the wire colors on another car. This has been a crazy puzzle to try to solve so it's great to have input from one of the experts! If nothing else maybe we'll be able to document this for those who follow. Someday when I've hunted down the other ends of the errant Z and ZN wires I'll be happy that at least there's a complete story on this board here for others. There sure seem to be a lot of cars that don't have functioning dome lights from the driver's side only, both TR and 512TR, so I hope that a complete understanding of the circuit will clear up this mystery too.

 

(I still haven't hunted down either the buzzer or the unnamed ignition switch connector).

On the 512TR, the ignition buzzer is a 1" square by 3 inch long component mounted under the right (passenger side) of the dash next to the turn signal flasher. If you are looking at C8, you are looking past these two. Easily accessible. The connector is mounted to the dash with a single 8 or 10 mm nut.

 

Here is a photo showing the flasher (black) and buzzer (blue) attached on the right side (it is the compnents themselves that attach to the vehicle, not the connectors).
I attached a jumper to the purple/black wire as it entered the buzzer (most easily accessible - remove the nut holding the component and the whole shebang drops right down. Or pull the connector off the top) and ran it to the driver's door pin switch. Problem solved for the 512TR. Now all doors and dome lights and puddle lights work as promised, ignition switch lights up and the ignition buzzer does its job.

Good luck on the TR's, gentlemen.

...Jimbo
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