Volvo vnl Multiple ecm's problems out of nowhere

2004 volvo vnl 780 3 pedal autoshift only 100000 original miles hasn't been exposed to salt or snow to much, only few times . The problem I have is when I started the truck on Monday morning out of nowhere abs light came on along with that engine ecu, transmission ecu, brake ecu ,light control module showed up on the information center. Truck lost speedometer, turbo gauge, turn signal indicator light and buzzer don't work (lights it self works fine just indicator on dashboard don't work) it works fine with 4ways on , very sensitive throttle ( can't control or keep throttle in one steady position) cruise control not working, not shifting in auto only can shift in manual mode and that is difficult to do .abs light on but seems like abs works . Checked all the fuses at battery box fuse box connections all seems to be very clean no discoloration oxidation and so on. Also checked all the ground cables, cleaned them as needed. This happened over the weekend (Saturday and Sunday was raining really hard) Friday was running perfectly fine and comes Monday this problem . Any suggestions, help much appreciated thanks.

 

Hi. Thank you for taking time to give me advice, I will definitely try that. Thanks again.

 

Can I take the brake abs unit off and open it to inspect and see if there is any signs of corrosion or is it sealed unit. Thanks

 

Good morning. First I wanna thank you guys for trying to help me out with this nightmare that I'm dealing with. Here is what I found, if I disconnect the green and yellow wires on one end of the plug and black both black wires on other plug ( don't know why they are black) right by the battery box ,my turn signal warning works I have turbo gauge working, no more brake ECU and no more light control module. Gas pedal response like it should . Here is what I don't understand , also I unplugged the 2 plugs right by drivers seat which are for the shifter (I have 3 pedal autoshift with push button) each set of plugs have data link wires green and yellow, one plug data link wires don't have continuity it shows 0.00 other plug which comes out also from the shifter side has continuity of 119.8 120.0 or so again testing both plugs on sifter side. I'm wondering if I have shifter it self shorting out and sending wrong signal to all computers. What your thoughts on that. Thanks again Andy. I'll try posting some pics.

 

Shifter plugs

 

The ones I'm holding are going through the cab and on floor board to ecm's

 

Shifter plugs