Temp Gauge / Tach / Speedo stopped working
 

Hey,

Recently i had some work done on my car. I had a new CV Axel and back wheel bearings replaced. Previously before that i had redone just about the whole front suspension due to the spring on one of my struts coming out of place.

I got the car back from the mechanic and was driving home when the tachometer dropped to zero on the highway.

Made it home and figured it was just some sensor going bad. Ordered sensors online and while i was waiting for them to arrive later the speedometer stopped working maybe 2 or 3 days after the tach.

I got the sensors the other day and replaced both transmission speed sensors, camshaft sensor and the crankshaft sensor. Started the car and the same problem The temp gauge and tachometer start with the car and after about 1 minute idle without moving they both drop to zero. I went through and checked / replaced all the fuses. Problem still occured. I currently have the ABS and TRAC lights on.

I figured it was a bad ABS wheel speed sensor. So just for troubleshooting purposes. I unplugged the abs sensor and tried turning on the car same problem with each one unplugged in different intervals. When messing with the back abs sensors i found a wire under the back seat that is next to the rear left abs sensor power hookup. I have attached a picture of this plug to the thread. When i unplug this power cable under the back left hand side seat my gauges are working properly. Could someone help me figure out what this wire is and why it would be causing this issue. I believe it to be a bad sensor shorting out the gauges (which would be why they work with this cable unplugged).

Any help or pointers would be greatly appreciated. Ive been hitting my head against the wall trying to figure it out.
https://cimg3.ibsrv.net/gimg/volvofo...a408a5d2e3.jpg
Unplugging this cable makes my gauges work again

As always Google can be your friend.

If your harness passes through the body to the outside rear of the car then....

Part number 307730380 on the harness.

https://usparts.volvocars.com/p/Volv.../30773380.html

https://usparts.volvocars.com/a/Volv...GR-303179.html

Thanks i had tried looking it up on google before but i couldnt find anything ( i blame the algo :P ) but i think it may be due to my javascript being disabled.

So earlier today i crawled under the car and checked the connectors to the haldex they seemed fine. The pump wire seemed a little brittle but i was reading that a bad pump would usually blow the fuse.

I tried turning on the car after disconnecting and reconnecting the haldex cables but the same problem was still occuring. I then tried pulling fuse 23 in the trunk for the AWD system. With the fuse pulled my gauges are working perfectly fine.

I checked the ground for the haldex unit which i believe to be under the left side back seat. according to a diagram that i found online
Electronic Wiring Diagram TP39261202

Does anyone have any ideas why plugging in the AWD haldex system would cause my gauges to stop working? the fuel gauge still works and the odometer on the DIM

I checked all the grounds that were easy to spot and i did not notice anything out of the ordinary.

Could a bad rear ABS wheel sensor cause issues with the AWD. When i plug in the haldex (in the case of my gauge not working) i can hear a ticking / tapping type of noise near the gear stick.

Would i be causing any damage to the car driving with either the cable unplugged going to the haldex pictured above or driving without the fuse 23. From reading other forums they made it sound like this would only disable the AWD function but i dont want to further damage my car.