Ferrari Testarossa Plastic Nut for Wire Harness on Protection Relay Box

There are two harness connections on the box with the protection relay. A small connector and a large connector. The nuts on both of the connectors break with time. It is more common that the large connector breaks first as it has a larger load due to the larger wiring harness.

 

The nut is part of the connector, which is sold as a complete assembly. It was made by a company named Tyco Electronics AMP, now named TE Connectivity AMP. You find the connector for sale by doing an internet search for the AMP number on the side of the connector. You can get them from TE connectivity or one of their distributors: https://www.te.com/en/product-206837-1.html
Here is one on Ebay: https://www.ebay.com/itm/235332510949
Image Unavailable, Please Login

 

I always replace the entire connector, which is an involved process and requires a pin removal tool to get the female connector pins out of one connector and into the other.
Image Unavailable, Please Login

 

Search using "C12 C13 AMP" for prior threads about those connectors. If it is just the tabs on the "nut" portion are broken off (or if the nut itself has broken in half), you can buy some new connectors per Brian's suggestions, and cannibalize the new "nut" off of the new connector, cut the old nut off your existing connectors (if necessary), and snap the new nut(s) onto your existing connectors (which avoids needing to move the pins over). The good thing is that the new nuts are from a version of those connectors that is a much better, more robust, design (the fine straight knurl on the stock nuts of the version that F selected was/is just destined to crack).

 

I replaced mine a while ago. It takes patience, not hard.

 

You certainly need to have good wiring and good connections in the C12 (and C13) round connector. The system will run open loop -- i.e., the EHA currents set to a constant 10 mA (if you are near sea level elevation; at ~5000 ft elevation they will be 7 mA) -- until the coolant reaches a temperature of about 150 deg F and the water thermoswitch on the Y-pipe opens.

 

Yes, it's a good sign, but not proof that the ECU(s) is working correctly in every way; whereas, if you had 0 mA during open-loop running = that would be bad for sure (assuming all the wiring/connections are OK).

 

Measuring the voltage on the single output wire of the O2 sensor (relative to ground) during closed-loop warm idle and confirming that it is "wandering drunkenly", every second or two, between lean (0.1~0.2 VDC) and rich (0.8~0.9 VDC) would be a good sign that the ECU for that bank is working IMO (but the mixture screw needs to be set correctly to give the EHA the ability to make that change over its operating range of 0 mA to 20 mA).

PS I can confirm that measuring the current in the EHA can be dangerous -- I accidentally shorted the two wires going to one of my EHA together and that blew up the ECU.

 

Many years ago Bosch taught us a test. If you have a way to measure exhaust gas ( And I consider tuning one or most diagnostics without a 4 gas tester a waste of time) ground the O2 connector and it will go full range rich. Put a 1.5 volt battery between O2 connector and ground it will go full range lean.
I make all adjustments with O2s disconnected to prevent their interference. Once done when reconnected both banks should lean slightly from 1.25 to about .6.
Make absolutely sure O2s are connected to correct bank. Reversed O2s cause one bank to go full rich and one bank to go full lean.

 

I would take that connector housing off and install all new pins on the melted wiring, as well as looking at all of the pins on both Lambda ECU's. I recommend using Rifledrivers test, as well as measuring O2 sensor voltage with the sensors connected one at a time, to make sure that they cycle across .5v.
You can make an EHA test harness with Mercedes Benz connectors and connector housings to measure the current without fear of damaging the ECUs.