1994 348 Spider All Gauges - Tail Lights Not Working

Do your hazards work, Anthony?

 

Relay "B" ("External Lighting") on the passenger footwell fuse/relay panel controls external lighting and instrument lighting. However, the hazard system bypasses this relay, so it's a good way of faultfinding.

Cheers

 

Probably just hearing the horn relay.

Does the engine run? Do the headlights work? Do the hazards work?

 

When you say "Turn signals dead", is that the lights themselves and/or the blinking indicator on the dash?

Also, any other recent work on the car?

Based on what you've said so far, this almost sounds like a wiring harness issue under the dash or in the front compartment.

I'd pull the front liner to investigate further.

 

Mice during winter storage? They love to gnaw on wiring... and it wouldn't be the first time.

 

Anthony, could you clarify what you mean by all gauges are dead. Just the backlighting or the needles, too? If your needles don't work, you have more serious problems.

It's sounding more and more like the external lights relay (probably shown as relay "B" in your handbook), but we may need a little more information.
The external lights relay provides power to instrument lighting, tail lights, HVAC ECU and more (although I can't see a tie-in with the mirrors yet).


P.S. Mike (probably) and I would still like to know if your hazards worked. There is a good reason we both specifically asked it. It's possible that your hazards work (by pushing the hazard button), but still have the turn indication inoperative.

 

Try the control relay for key operation. Step pad fuse box. 5th relay from the left. Top row. Thats in a euro box. Probably the same. Letter E. Had a similar problem and it was that. Worth a go.

Its a common relay in the box so try substituting to check.

 

http://www.ferrarichat.com/forum/348-355-sponsored-bradan/68444-help-f355-dash-tail-lights-not-working.html

Scroll down to see the solution for the 348

 

Here is a link to my thread. Scroll down to the bottom. This shows a RHD fuse box so maybe reversed in your car.(Shows a LHD in my handbook) Looks like you have similar failures to me. I will say this fault was intermittent and occurred only occasionally and would clear after a short drive. Eventually it stayed long enough for me to diagnose by checking all the faults against the wiring diagram and tracing back. This relay was common to all. Substitution cured the faults. Not seen the issue since. It was a bit baffling at first.I would try this first before pulling your car apart. Who knows?

Ferrari 348 engine bay and rear end restoration. - Page 28

 

+1

Good point. That was my second choice of relays Frank, try the windscreen wipers (ignition on). If they don't work, this will prove that relay "E" is not ok. Looking at the wiring diagrams, this relay also provides power to mirrors.

 

To confirm Pangea's comment, I traced the wires from relay "E" and the systems connected were:

Fan motor for cabin temperature sensor
Tachometer power
Oil pressure gauge power
Speedo sensor and gauge power
Water temp gauge power
Power for numerous warning lights
Power for aircon compressor clutch relay
Left bank cat TCU power (would this cause the car to run rich?)
Oil Temp gauge power
Fuel quantity gauge power
Turn Indicators
Reversing lights
Glovebox light
Windscreen wipers
Brake lights
"Electric water pump for heating" (?)
Aircon fan speed controller

... and probably a few things I've missed

 

Figures ABB.4a and ABB.4b (pages L32 and L33 ) of the WSM's wiring diagram (348 Spider - Euro and USA) shows that Relay "e" receives power through its pin/blade 30. In other words, straight from the battery (152A - Positive battery connector).

Just so we're on the same page, Relay "e" (in the front compartment's fuse box) is primarily for the "Control relay for low beam headlamp actuation (BOSCH 0332014113)".

I'd suggest swapping two relays of the same type (0332014113 ?), and see if the problem moves. If the same symptoms occur, then check "152A - Positive battery connector". If the move, then obviously it's a bad relay.

Relay "e" is the same type as relays b, c, d and f (according to the wiring diagram). However, "b" shows as "available", which tells me it's a spare.

 

Well, everything on the car gets its power from the battery/alternator, one way or another. It's what activates the relay that determines when the device gets power (a switch, an ignition key, a control unit, etc). In this case, it's the ignition key in ON.

 

Thats great. Happy it worked out for you.

 

Strange, "B" is listed as "External Lights" in the workshop manual. The diagram I have also shows it powering fuse 10... Park lights, licence plates lights and instrument lighting. "B" also has dual contacts.

Lighting Diagram

Hope we're not putting Ferrari technicians out of a job here (I still need them)

Cheers

 

Your diagram is really nice, thanks.

These wiring diagrams are always interesting. I didn't get a chance to review the rest of the relays, their differences and variations.

Following up, Page L25 of the Spider wiring diagram shows "Available" for Relay e. However, Page L26 shows "Control relay for actuation of external lighting".

Notice too that a different BOSCH relay is specified (0332014113 and 0332015006 respectively).
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Excellent. So glad to hear about quick, easy and low cost repairs.

 

Interesting, thanks... I may have to add some precautionary notes to that diagram. Perhaps they incorporated the functions of relay B into another one (on later cars)... Relay "E" seems already overloaded however, controlling power to fuse 5, 6 and 7.

Work in progress...

Instruments Diagram 5b

(I may have made a few mistakes in this one... the colour codes are not clear in the original diagram)

 

Ian, thanks very much indeed for sharing your enhanced wiring diagrams! If only the factory had been considerate enough to do that to begin with...

For what it's worth, I have the section of the original factory manual which includes the wiring schematics. The color codes on the originals are far superior to the PDFs, which are illegible in some cases (as Wade & I can attest from experience). If I can be of assistance in clarifying anything or confirming color codes feel free to PM me. I'm happy to do anything I can to assist you in creating your vastly superior schematics.