348 348 Speedo trouble

It depends on what it is shorted to (and which wire you are talking about).

No fuses have blown, so there are no shorts on the power wires. On the signal wire you want no voltage when the key is off. When the key is on, you want voltage. When the car is moving, you should see +7.0 volts to -0.7 volts. If you see 12 volts, you have a problem.

 

Raoul, can you identify the colours on the wires on connector 115? I'm not sure my diagram wire colours are correct.

Image Unavailable, Please Login

1) HG? (Oil pressure low?)
2) Should be RB, but looks like BR? (Speed sensor signal or is this a battery power sense wire going to the alternator)
3) B or G? Is this a standard Ferrari wire or a repair? (Alternator regulator power?)
4) H? Water temperature sensor (for gauge)
5) VB (Speed sensor power?)
6) B (starter)
7) B (starter backup)
8) GV (alternator warning light?)
9) HB (water temperature switch)
10) RN (battery power sense wire to alternator or speed sensor signal to instruments?)
11) HN (oil pressure sender signal to gauge)
12) VN (HVAC compressor)

The newer cars have 12 wires instead of 9. I'm trying to figure out what the extra wires do.
6 & 7 may be duplicate wires for the starter solenoid (to carry extra current)
One wire may be a sense wire from the battery. One wire may be alternator regulator power.

Thanks!

 

Ian, looking at the wiring diagram for the Spider (Section L32 Fig ABB.4a) it shows only 7 wires for Connector 115. Note, 4a is the Euro version and 4b for the USA. But both are the same for C115 (number of wires, color codes, etc.).


Image Unavailable, Please Login

 

Wires - number and color code:

7 - HG
5 - HN
10 - H
3 - HB
2 - GV
8 - RB
11 - VB

 

I'm unfamiliar with your connector. Maybe wait for Ian (or another) to reply?

Is yours numbered like this?


Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login

 

If not, maybe match by the wire's color codes. Remember, the wiring diagram's color codes are in Italian.

 

Look closely at Ian's Post #54, then go look at yours. You might need a magnifying glass on yours.

 

Raoul has a rectangular connector which resembles the 355's with some colour/pin variations. The numbering system I've used in post 54 is based on the numbers I found on the connector of my F355.
Raoul, perhaps when you get back to your car, you could clean the female connector and see if there are numbers on it. My connector has 2-3-4-5 on the middle section (There is no room on the outer section of the connector for 1 & 6).

In summary... speed sensor pins 8 & 11 on Wade's diagram are labelled 8 (RB) and 11 (VB). Looking at Raoul's photo (with my numbering), 8 & 11's colours are most likely GV and HN, so not the pins for the speed sensor. On the Ferrari F355, the speed sensor has pins and colours - 2 (RB) and 5(VB). The F355's colours are a perfect match for Wade's 348 diagram's speed sensor, but not for pin numbers.

As Wade suggests, perhaps colours are the better way to go, but I don't know if Raoul has an RB... and VB is on pin 8 (a mis-match with the diagram). The only way to confirm these pins is to do multimeter checks. Unfortunately, if you have a short on one of your wires, this may complicate your wiring tests.

Note that there is a colour change when one of the speed sensor wires goes through the relay panel. RN becomes RB. There is an RN wire on Raoul's plug (pin 10). Perhaps this is another possibility.

 

Just after I bought the new speedo I sold the car, and the new owner was interested in having it repaired to "keep the mileage correct" (new speedo with only about 10 miles on it by then). Upon arrival he send the dead speedo to a repair shop nearby (he's in California) but they said it was not repairable, so he sent it back to me.

Right now it's a "back burner" project but it doesn't look to promising. I need to repair the plated holes (i.e. "lands") first.


Image Unavailable, Please Login Image Unavailable, Please Login

http://www.circuitrework.com/guides/4-5-1.html

.

 

Notch?

Do you mean the plug (connector) in your photo? Isn't that the sensor side of the wire harness? If you're not getting voltage on the car side of the connector, then either the connector pin numbers are not matching the diagrams or you have a power problem. Re-installing the speedo is not going to help restore power.

Did you make a list of the wire colours and pin numbers on that connector? It will be useful for others with that type connector (who have wiring problems)

 

The +12V supply to the speed sensor should be the Green/White wire. You should test for +12V at the pin in the fixed half of the connector, not on the one you are holding in your hand.

 

I'm not sure I understand. You have a correspondence? The image you have posted in post #72 was a theoretical picture partly based on illegible F348 wiring diagrams and a F355 plug. I think the wire colours in your photos (in post #54) are slightly different to the image above (?)