In the 1994 Volvo 940, the relay for the 4th gear is typically located in the engine compartment, specifically in the relay/fuse box. This box is situated near the driver's side fender. To identify the correct relay, refer to the diagram on the cover of the relay box for the specific layout and labeling. If you need to replace it, ensure the vehicle is turned off and take appropriate safety precautions.
Remove the fuse from the fuse box. Or remove the relay.
4th gear
It's the overdrive engage button, which is like a 5th gear. It only engages when the gear lever is in 4th gear and it can be operated without depressing the clutch.
Volvo is a great technology in vehicles. Shift light indicator mean the indication given, that the vehicle is now comfortable to shift the gear. For Example, the Volvo car is moving on 60 mph and you are moving on 4th gear the shift light indicator will blink reminding now you can shift a gear further mean you can move by gear 5.
I removed the Relay.......Cut wire From Trans Connector/Heat shrink...... Ran wire to connect shifter wire (one side)...Replaced switch with off/on switch/led ....Super glued on shifter...4th Gear switch (forward position)...3rd Gear back position...Other side of wire connected to accessory power.... Problem solved...Switch $ 8.00 at Radio Shack... Dedicated Shifter...No Relay....
Overdrive relay switch behind the middle air vents..... Manual Transmission: the wires sometimes break if it is the type with the button on the gear/knob/ stick........... if it is a manual transmission.......the switch on the gearbox which tells when 4th gear is engaged can be faulty.....and will not allow the overdrive to engaged.
On the transmission!!
I had this problem about ten years ago on my 1990 740 GL. The problem was actually a defective relay. The relay is controlled by the button on the gear shift knob and is used to prevent going into 4th gear when towing. It is located among all the relaysbehind the ashtray in the center console panel. Behind all the fuses. At that time I went to the Volvo dealer and bought a new relay and from that worked out which relay to change. In those days it cost me about $45.00. Has worked fine since then. Good luck. You must to isolate the source between the Overdrive relay or the Overdrive solenoid and the overdrive switch at the shifter. Ignition on, engine off - Push the overdrive switch, if you can ear a light click the relay and the switch are probably Ok, check the overdrive solenoid at the transmission. If you don't have the click you have to trouble shoot the switch to see if it's working. - Check continuity to the switch and the 12 volts. - If evething seem to be OK, change the Overdrive relay Good luck
is this a manual box with the button on the top of the stick to get 5 st overdrive gear drive in forth up to 40 mph then press the button overdrive light green light now on press to come out of overdrive or change down a gear to third.
There could be several reasons why the 4th gear in your 1992 Mercedes 300 SE may not engage. The reasons can include a gummed up solenoid, a wiring issue, or a relay switch problem.
It is controlled by the sliding switch on top of the gear knob. Switch in the forward position is off and in the back position on. It will only engage if the car is in 4th gear. The 1975 and 1976 models were known for having a weak overdrive unit (5th gear) so your actual problem may be the unit itself is bad
The 4th-generation car was upgraded in 2010. The upgrade was mainly the heated seat relays that are located on the right side of the seat.