91 240 Turbo Auto - Headlights/Wipers/Thermostat/O2 Sensor??

[jamesrk4unl]

I am very thankful for finding this forum and in advance I want to thank anyone for their time and the responses they provide. I do appreciate it! This is a rather lengthy post so here is a quick snapshot -

1) Headlights are not functioning properly
2) Windshield wipers are not functioning properly
3), 3A), 3B), Heating/thermostat/power issues

I purchased this 91 Volvo 240 Turbo Automatic with 125,000 miles last fall. The car ran as well as one could expect until it got really, really cold (as in single digit high temps - Fahrenheit). Since then I have the following issues I desperately need help with!! (The car is mainly being used on the highway as I do a lot of driving for my profession.)

1) My headlights stopped working altogether. One day I left the car idling, so it stayed warm, while I went inside a property I was posting signs at (one part of what I do is preparing foreclosed houses for auction). While inside, BOTH headlights turned off at the same time. The car appeared to still be running fine and my sister who was in the car said she did not notice any sounds or anything - "They just shut off all of a sudden."

When I returned to the vehicle, I turned the car off for a few moments and checked the fuse which as far as I can tell is still operational. I restarted the 240 and turned the headlights on - there was a click and the headlights turned on with one problem. The headlights were on, but ONLY the high beam headlights were working and the blue "high beam" light was on. Regardless of how much I played or fiddled with the lever ONLY the high beams would work.

Now fast forward a couple of weeks. I kept driving with high beams since they were not really that bright anyway. I pulled behind a car at a stop light around dusk to notice that my lights were not reflecting off the car stopped in front of me. I pulled onto a side road and sure enough - my headlights were no longer working at all. The parking lights, brake lights, and dash lights were still functioning properly.

I replaced both headlight bulbs and still nothing. I replaced the fuse and still nothing. Would I be wrong to assume it is something electrical? I have a Chilton's Repair Manual that leads to me to believe the "headlamp motor" needs replaced. Any ideas? Agree? Disagree?


2) My windshield wipers stopped working as well. Is there any troubleshooting advice? The only suggestion the Chilton's Manual has is to replace the "windshield wiper motor" which involves removing the glovebox and some retaining bolts which sounds a little tricky for a first timer.

3) Need to replace "thermostat" and/or "O2 sensor" ?? For this one, I am going to describe two isolated events that I do believe may both be related to the heating/colling system. I want to start by just writing about WHAT happened followed by the suggestion I received from a local mechanic.

3A) The first event happened on a day where the temperature was no higher than five degrees Fahrenheit. The thermostat on the dash did not warm up at all after 20 or more minutes of warming up. I contributed this to the cold and had an appointment so assumed the car would warm up on the way. The thermostat did not budge. Could it have been frozen because of how cold it was? My appointment lasted a little more than an hour and I left for home. About six blocks later the thermostat shot up almost all the way and a couple blocks later was at its highest point. I was traveling over a bridge on an arterial road with no place to pull over for a few blocks. I turned the heat on all the way (even though it was still blowing cold air) - isn't this supposed to help cool down an overheating engine? If I remember right, there may have been some "gushing" sounds when the heat was turned on. A couple blocks later there was a loud snap and antifreeze sprayed all over the windshield (without my wipers working now no less). Upon inspection, the upper radiator hose had exploded. I replaced the hose and it has held up so far as I knock on some wood. I am afraid this may be nothing more than a band-aid. Would this suggest that I need to also replace the thermostat?

3B) I was traveling on the highway and was forced to play games with the heat the whole way. The car warmed up as it usually does, but the heat was not as warm as it had ever been, but was nonetheless warm enough. After 20-30 minutes the heat turned colder and colder and the thermostat on the dash was dropping. I turned the heat off and the thermostat rose again. When the thermostat returned to its normal level I turned the heat back on. Warm air came out and after about 10 minutes the air began cooling again. I repeated this over and over again the whole trip. Total mileage was approximately 150 miles. At this point, I am approaching my exit off I-80 and my 240 begins to lose power. I pressed the accelerator all the way and was able to keep it above 50 mph long enough to reach the exit ramp - I had been maintaining a speed of 65-70 mph. I exited and came to a stop light where I had to stop and the 240 stalled. I tired to start it a couple of times. It would turn over, but it would not engage. I called for a ride and waited about 20 minutes. During the wait I periodically tried to start the 240 to no avail. Of course, when my ride arrived I tried to start the 240 one last time and it all but fired right up. Since it was now almost dark without headlights I drove the 240 to a parking lot and picked it the next morning. The next morning it started right up and I was able to get it home with no problems except the heat/thermostat was still not functioning properly. What would cause the 240 to lose power like that on the interstate? Could the O2 sensor be responsible?

I have been using a different vehicle, but from time to time have used the 240 on short trips around town and have not experienced any additional problems. There is still the heat/thermostat issue.

I was told by a mechanic not too familiar with Volvo's that it sounds like the thermostat and O2 senor stopped functioning properly during the deep cold. I am by no means a mechanic but from what I have read in my Chilton's Manual I would be able to replace both the thermostat and O2 sensor if need be. However, I do not want to just start messing with stuff unless replacing them could lead to a plausible repair for the problems I am having.

Any suggestions, advice, tips, tricks and the like are all greatly appreciated. Is it too much to ask to have headlights, wipers, and heat that work? Thanks for your time!

[billofdurham]

Welcome to Matthew's Volvo Site.

1. There are two relays associated with the headlights on this model.
One is the headlight high/low beam relay which is located next to the battery. The other is the headlight relay which is located under the left side of the dash to the left of the steering column. In fact you will find two relays at that location. The top one is the headlight relay and the bottom one is the fog light relay.
In view of your symptoms I would be looking at the high/low relay first. The only way to check it is to replace it with a known good one.

2. Check fuse #2. However, as that also covers the horn if that unit is working it is not the fuse. Do the washers and headlight wipers/washers work?

3A. The gauge on the dash is the temperature gauge not the thermostat which is in the engine cooling system. It would seem that the thermostat has developed a fault and will need to be checked/replaced. Reading the symptoms I would say that it initially stuck in the open position as the temp gauge did not move and presumably there was no heat to the heater as you later report. It then seems to have shut itself completely allowing the build up of heat, and pressure, in the cooling system which lead to the hose blowing apart.

3B. It would appear that this time the thermostat had again stuck in the open position which meant that the engine temperature was fluctuating. Normally if the coolant temperature has reached working temperature and this starts to drop the thermostat will close slightly until it gets back to the proper working temperature. By turning up the heater you were bleeding heat out of the coolant and that and the cooler air outside meant that the coolant was not at its correct temperature. The engine control module relies on the temperature of the engine to regulate the fuel supply to the engine and if it is getting a 'false' reading it will make the wrong decision which could account for your stalling problem. When the engine was totally cold the ECM would allow the engine to restart. That is in basic terms, not totally technical.

I agree with the mechanic in his diagnosis of the thermostat but the oxygen sensor.....?

Your car is fitted with an On-Board Diagnostic unit in the engine compartment from which you can read fault codes. If the oxygen sensor is playing up a fault code should have been set. To access any codes see: https://www.matthewsvolvosite.com/forums ... c&start=12. This does apply to your car as well as the 740.

The thermostat is easy to replace and I would definitely start there. If you wish you can check it by suspending it in a pan of hot water and see if it opens. After that check for fault codes.

Any questions, ask.

Bill.

[jamesrk4unl]

1. There are two relays associated with the headlights on this model.
One is the headlight high/low beam relay which is located next to the battery. The other is the headlight relay which is located under the left side of the dash to the left of the steering column. In fact you will find two relays at that location. The top one is the headlight relay and the bottom one is the fog light relay.
In view of your symptoms I would be looking at the high/low relay first. The only way to check it is to replace it with a known good one.

Thanks again for responding Bill!

You hit the headlight issue on the head and saved me a lot of time! It was determined that the high/low beam relay by the battery was malfunctioning. The wiring diagram I was using made NO sense until I opened up the relay to find an almost ball-point pen like mechanism to switch back and forth between high and low beam. Some of the "high-quality" plastic (sense sarcasm) had melted or disintegrated preventing the needed electrical connection.

In the meantime, I decided to go sans high beams and removed the high/low beam relay altogether and created a direct connection. Not a permanent fix but one that will work for now - and it saved me the cost of the relay!

I am hoping to have the time to troubleshoot the wipers real soon. Any suggestions on where to start? FYI - the #2 fuse is in working order.

In addition I will be getting back to you very soon regarding the thermostat. (On a good note we had some unusually warm weather 50+ degrees Fahrenheit and the 240 ran as well as it has since I bought the car last fall so this got placed on the backburner. The heat was warm and there was no stalling or sluggish performance.)

Thanks again for your reply!

[billofdurham]

Glad to be of help.

Regarding the wipers the first thing is to find out if power is reaching the motor. Do the washers, headlamp wipers/washers work? If they do this would just about rule out a faulty switch. Unfortunately, you are going to have to access the motor to check at the plug. This is not too difficult as you only need to remove the panel under the dash and the demister hoses to reach the motor/plug. If you have power to the plug then the motor will probably be dead.

Bill.