2001 V70 XC - Rear Brakes Lights Do Not Come On Topic is solved

[dbm123]

Looks like I have an issue with the relay for the rear brakes on my wife's 2001 V70XC. The top rear brake light comes on but the side ones do not. The rear relay panel is partially concealed behind an interior panel. I don't see anyway to unbolt that or whatever to get to the relay to change it. Ideas?

[dbm123]

Anyone?

[abscate]

Check the bulbs first, then the wiring. There is a weak spot on the P80 chassis of the left side rear hatch hinge, where the wiring often breaks.

Search threads for 'rear wiper inoperative' ( the same wiring break issue occurs here)

[dbm123]

I changed the bulbs. I guess I will search for the thread you mentioned. But -- I still want to know how to remove the rear interior panel in case I need to get to the relay box. Anyone????

[cpo man]

The rear interior fuse panel should be in the rear hatch area on the left (driver) side if you are standing at the rear of the vehicle looking forward. It just clips into place, no screw or bolt. The brake lights relay and the rear "fog" light relay are wired similar enough that one will work for the other. I had this same problem as well. Just swap out the relays and order a new one on-line. I think I paid $5 or so. Swap in the good one when you get it and put the rear "fog" light relay back where it came from. Easy fix....

[mikealder]

An earlier post of mine covering the brake lights with an explanation of how it works:

First the diagram which I have colour coded to make it easier to follow in the text below:



Lets start at top right with the fuse 11B/12 this feeds battery voltage to the brake pedal switch, with the pedal switch depressed the 12V travels through the yellow wire going through connector 54/3LG pin 12 before going to the CEM arriving on pin B4. The CEM then inverts this signal prior to feeding out a discrete signal to the REM on the green and yellow wire routing through connector 54/43 pin 13 which is under the left hand side of the rear seat base.

The REM now does two things with the 0V switched signal going in on A4, firstly it provides a +12V output on D4 which is a yellow and red wire this passes through the tailgate connector 54/78 pin 3 where it changes to a yellow wire routing to the center brake light. The other thing the REM does is to energise the brake light relay, can you hear/ feel the relays click when you (or a helper) presses the brake pedal).

+12V is fed through fuse 11D/3 which goes to the brake light relay, when this relay is energised it feeds power out on the yellow wires to the trailer socket 54/51 pin 4 and to the Shunt RSH6 which provides bulb failure detection for the brake light circuit, the yellow wire from the center of RSH6 feeds power to fuse 11D/14 (7,5 Amp rated). You should check that RSH6 Shunt is still fully connected to the REM or did it get disturbed when you popped the relays out or changing fuse?

The output of fuse 11D/14 is a green wire feeding power to splice 53/667 which is in the main wiring look under the REM, the splice is a small black heat-shrink covered metal barrel containing three green wires. The two green wires then connect to the brake light bulbs on both sides of the car.

Try fitting a new 7,5A fuse to 11D/14 then see if the brake lights work, if not take the REM off its mounting structure and have a good look at the rear of where the brake light relay is located, check the two yellow wires are still connected to the relay base and not damaged as in burnt out. - Hope this helps (My money is on the brake light relay starting to fail) consider swapping RMI4 (reverse light relay) with RMI5 (outboard brake light relay) and see if the fault moves to the reverse lights, if this is the case replace the relay - Mike

Some of the above troubleshooting was for a specific fault, in your case as the center brake light is working I wouldn't be too worried about the tailgate hinge point.

If you have a voltmeter set it to measure DC Volts (20V range is ideal) then connect the red meter lead to the + Terminal of the battery, connect the black meter lead to pin A4 on the plug that feeds the REM with the brake light signal then with the help of an assistant pressing the brake pedal check your meter reads 12V with the brake applied, the +12V signal from the foot pedal switch is turned in to a 0V/ open circuit by the CEM, the REM then uses this signal to switch on the relay for the outboard brake lights and turn on the driver circuit to illuminate the centre LED brake light - Mike

[db130]

Mikealder,

I have had an issue with the REM where the two left brake lights weren't working. I have tried swapping out the brake light relay and the brake light shunt and also unplugging the REM as well as the battery.

Unplugging the REM+battery brought the brake lights back for a couple of days, but now it's the left brake light that won't light up. Yes, I have checked the bulb and it is good. Because the 3rd brake light and the right brake light work, it can be assumed that power is at least getting to outboard brake light splice 53/667, right?

If I connect the multimeter leads to the 2 green wires that connect to the left brake light bulb then press the brake pedal, I should get 12V at that point, yes?

[NC2001v70]

This sounds a lot like the dreaded rear brake relay upgrade to me. The relay for the rear brake lights required an upgrade from the original . The original was a one piece relay and the replacements are 2 piece. The part number is 8651661. RMI5 is the placement. You will need to order 2 of them. One for left and one for right. The replacements are direct fit and are available from FCP and IPD for about $17.00 usa each. Replacement is fairly simple. Remove everything from the rear of the car as it will make it much easier to access the panels that need to be removed. Fold down the rear seats. Remove the cargo area cover if you still have one. Remove the panel that covers your rear fuse box. The panel that needs to be removed and covers part of the rear fuse box, has a 10mm. bolt to remove first where your cargo cover fits into the panel. After this the top part of this panel needs to be snapped out and pulled out out of the metal clips holding it along the top, hinging the panel away from the top side of the wall of the car where it meets the floor. Once removed, the rear relays are accessible and all contacts should be cleaned on all relays while your in there to prevent intermittent issues with the others (Turns and back up relays and all others). Just borrow a nail file from the Wife and spend a few extra minutes with it, and you will find a lot of the light gremlins will be tamed. I guess you can tell I didn't the first time, and had a crazy weekend trying to chase down some intermittent light issues. Good luck.

[db130]

My issue turned out to be simpler in nature; a bulb that looked good visually but failed continuity. You have no idea how happy I was to see the issue reproduced on the other taillight once I swapped the bulb over. I keep the bulb at my desk as a reminder to check the simple stuff first, even if it is unlikely.

[xHeart]

Here is a photo of cargo Relay & Fusebox.
After checking fuses and replacing bulbs, removed bulb # 1156 with IPD/Flosser 6671.
Now, I am thinking it is relay.

Any input on replacing Relay PART NUMBER: 30765030.
Both left and right lamps' brake light is not coming on.

10mm bolt in orange circle.

Parts diagram http://volvopartslisle.com/assembly/74823797/Control-Units

Cargo Fusebox