Cooling Fan Relays, Gasoline Smells, & Other Junk To Fix

jackmac94 · Post by **jackmac94** » 02 Aug 2013, 14:25

I am still new to posting, I just wanted to say I have been looking for a proper thread concerning not only replacing the cooling fan relay but also what to look for in regards to why it will not turn the fan on.
I have found a proper wiring diagram for the cooling fan relay here:

Also a very nice simple diagram (for people like me) under attachments. (It's a picture from an ebay posting so I had to upload it, I did not want to add a link without a page to come up)

and have also found a video showing how to test a simple relay here:

My problem has left me a little more in the dark than what some of the various threads concerning relay replacement and also cooling fan troubleshooting information can provide.
My situation is that i have a 1995 Volvo 850 GLT wagon sitting in the back of my woodshop garage. I recently did/replaced the following:
raditator, (it had a 2" long split at the plastic seam near the top passenger side)
the airbox, (the thermostat inside the airbox was stuck in a position that let only warm air from the exhaust side come through instead of the almost-as-warm front side Alabama air)
thermostat,
the intake manifold got a new gasket,
throttle body cleaned out,
IAC valve was cleaned,
replaced the EGR valve, (it is a '95 so the stupid thing still had an EGR valve line attached to the intake manifold)
and replaced the PCV system entirely and even redid the flame trap line with 5/8" heater hose.

So what I am left with are two problems that need fixin':

First, and more importantly, I need to find out why my cooling fan will not start. I have checked all fuses in the first block by the driver side engine bay.( I have not found another fuse block but someone may know where another one is hiding) I have also bought and installed a new KAE cooling fan relay and have hooked that up more than six weeks ago that did not start the fan even when I jumped the contacts for what I believe go to the engine coolant temperature sensor. I have also directly jumped the fan from the battery, it works. I have also jumped (accidentally) the HOT AT ALL TIMES fan power line from the harness to the what I guess is the green ?high speed side of the circuit? I dont know, all I do know is it turned the fan but not very fast, maybe because it was a low current going to where a high side circuit should go??? Anyways I am just completely stuck on trying to get my fan on.
*Side note* No, my cooling fan does not turn on when I turn the A/C fan inside on. My setting inside the car is all the way cool and set to fan speed one. (its manual control)
So I know there is something there not letting the power turn the low speed of the fan on ?right?

Second, and not as important but nonetheless needs to be resolved, either my manifold is leaking or some other line is because I can smell a terribly strong scent of gas. I can also hear a small vacuum leak but from my understanding that is a totally different problem. (but i am literally adding only days worth of experience to this confounded problem so that shows you how much I know)

If anyone has any suggestions on where to tackle this problem please let me know. I am in a bit of a bind because I will be moving soon. Also, I am sorry if I am not posting this in the right place or if I should even be posting this at all and come to find out from some well read contributor tells me (politely hopefully) that the problems I have are actually very menial and all I had to do was type in the right keyword to find the answer. (I already tried that a number of different times, just sayin')

Thanks for reading and in advance for any advice you think may help.

Post by **Ozark Lee** » 02 Aug 2013, 19:27

You are making life way too difficult.

The video is not of a Volvo with a 2 speed fan and its utility is pretty low when it comes to the way the Volvo system works. Most manufacturers have a simple thermostatic switch and a single speed fan. Rather than do something simple Volvo decided that technology better suited for the space shuttle would be better, they even went to the guys that designed the 5 cylinder PCV system for additional advice.

The way the Volvo system works is that the ECU tells the fan when to come on and at what speed it should run, high or low. While I don't have internal schematics for the ECU and I don't have the source code for the firmware I can tell you that two of the most important inputs that control the fan speed are engine temperature and air conditioning system pressure. The system has three states, High Fan, Low Fan and No Fan. The latter state occurs more often than you would think. It is not uncommon on even a hot summer day for the fan to never come on unless the air conditioning is turned on.

The AC system pressure tells the ECU that the AC is not only turned on but that it is actually operating. If the AC system has a problem and the compressor isn't running and building pressure the ECU, correctly, treats it as being the same as not having the AC switch on at all. Any time the AC is functioning, even in defrost mode, the engine cooling fan should run.

If the engine temperature rises above the target temperature mapped into the ECU then the ECU will tell the fan to kick into high speed mode.

Here is how you test the fan relay and the fan.

To test both the relay and the fan with one test, unplug the center connector that has the Yellow wire and the Yellow/White wire. Ground each of the relay pins that the center connector plugs into, one at a time. The fan should turn on and toggle between high speed and low speed as you alternate grounding the relay pins.

If the fan does nothing and the relay doesn't even click check the large Red wire for battery voltage. The wire to the fan has a fusible link which can blow. It is extremely rare for it to do so but it can happen.

If you have battery voltage at the large Red wire you can fashion a jumper wire and go between the large Red wire and, individually, the Red or the Green wire on the fan connector. The fan should run and change speed as you change from one wire (Red or Green) to the other.

The major flaw on your schematic is the the Yellow wire and the Yellow/White wires don't have a closure between them to make the fan operate. The relay is controlled by those wires, individually, going to ground.

...Lee

jackmac94 · Post by **jackmac94** » 04 Aug 2013, 16:44

Ok! So I tested the relay the right way this time and...VOILA! It worked! So now I know my relay and fan both work properly and I have become more knowledgeable on why/when the fan should come on.

Thanks ...Lee for your response. I hope someday this will help a Volvo owner too. It helped me!

I haven't tested my ECT (engine coolant temperature) but I did clean the connections and insulation because they were pretty much toast, the soft plastic housings crumbled to pieces when I took the sensors wiring out.

Also, I tried cranking the car up after months of it being laid up and it would not start.
I checked the electrical (to the best of my ability) and the electrical seemed to be connected properly. So I listened for any problems and sure enough something was wrong. Since it has sat a while and because I didn't fill the tank up properly before I let it sit, I believe the fuel pump gave out/died/ whatever.
Considering the car has close to 200,000 miles and the fuel pump has never been replaced since I have had it I figure no power going to the fuel pump relay (when I checked all the connections for it with a test light and no power came through with the key in the On II position) and the lack of a fuel pump "humming" when I turn the ignition key on tells me that the fuel pump is bad, right?

So I figure that is my next project, FCP seems to have a pretty cheap build kit compared to how much a whole new unit costs. I will keep the thread up to date on what is going on. Here are some pictures of what I have done so far to the cooling fan relay connections:

Post by **Ozark Lee** » 04 Aug 2013, 17:09

The lack of power to the fuel pump indicates more of a problem with the fuel pump relay that it does with the fuel pump itself. You know the pump is bad when you do have power at the pump but it doesn't do anything. You can test the pump by removing Relay 103 and using a jumper wire between the socket positions associated with pins 15 and 87 on the relay and see if the test light comes on and the pump runs.

If the light comes on and the pump runs then the relay itself is likely bad. You can either repair it or just replace it.

I would never try to talk someone out of preventively replacing a fuel pump, they have a nasty habit of failing at the worst possible moment, but be careful on what you replace it with. There are a lot of junk parts in the aftermarket and you might be better off with a 200 k mile OEM pump that a cheap Chinese repair kit. Walbro makes a good quality replacement pump cartridge but you need to be careful on where you buy it. Walbro has a good name and whenever there is a good quality product the counterfeits hit the market to cash in. The down side to even a real Walbro pump is that they are noisy.

In the original title you mentioned a fuel smell, did you ever track that down?

...Lee

jackmac94 · Post by **jackmac94** » 04 Aug 2013, 22:38

No I never did track it down yet. I didn't smell any gas this last time I tried cranking the car, although I figure there can only be so many things wrong when you smell gas.(Injectors not seated properly, fuel pressure regulator gone bad, cracked hoses, ect.)

So looking at my diagram I can see that power travels through the blue/red wire from the fuse box to my fuel pump relay and that the relay should only have four wires going to the relay, but my relay has five pins...

Also, there is absolutely no power going to the relay sockets. I guess it never hurts to check all the fuses again to see if one has blown. I am out of town as of this evening so I wont be able to do anything until Saturday. I will still keep the thread up to date as best I can.

Thanks for the support! I really do appreciate it!

rcannon · Post by **rcannon** » 05 Aug 2013, 01:27

I had a fuel smell and discovered a plastic line disconnected that runs under the car on passenger side back to tank I guess. Mine was missing a hose connector between to plastic tubes, located under the passenger. It is black plastic about 8 mm dia.

Post by **Ozark Lee** » 05 Aug 2013, 06:47

The 5 pin relay does the same thing as the 4 pin but they added an extra small pin to split up the current flow across one of the pins. The 5th pin is in parallel with one of the other pins so it doesn't add any extra elements to the circuit. I don't have any of the 5 pin versions in my parts box so I'm not 100% sure which pin it is that got the extra pin.

The pin 15 and 87 jumper works equally as well on the 5 pin version as it does on the 4 pin. If the relay is bad and you can't find a 5 pin replacement the 4 pin relay will plug into the socket and work fine.

...Lee

jackmac94 · Post by **jackmac94** » 05 Aug 2013, 16:19

rcannon, very good to know. When I try to find out my no fuel issue and get it resolved that will be my next concern since I have many worn out/cracked tubes. Thanks for the input.

Also, thanks ...Lee. Nice to know as well. I was stumped since I saw all the replacement relay pictures had four pins.
My plan for when I get back will be another fuse check to make sure there aren't any blown. Then jumping the sockets 15 and 87 for the fuel pump relay and see where that takes me.
Uhh....waiting is so hard to do!!!

jackmac94 · Post by **jackmac94** » 18 Aug 2013, 06:39

Ok, so I checked the whole fuseblock to make sure there were no fuses blown at all and none were found to be blown. I also used my testlight to find that the socket 15 for the FPR does have power. Next, I used a paperclip to jump the sockets 15 to 87a. Still nothing. I also checked to see if there were any humming noises when I left the key in Ignition 2 position and I tried the screwdriver-to-fuel-rail technique, but no success. I even left the seat cover over the fuel pump access port open to see if I could here it from inside. Nothing. Does this mean that I am falling on the Fuel pump as the bad component?
I will upload pictures when I get the chance.

(one more question) Would my fuel pump quit because I do not have a charged battery? It seems like the last few times I tried starting the vehicle my battery either had no or little power to even get the starter motor going. Would that affect an old fuel pump that needs power?

Post by **Ozark Lee** » 18 Aug 2013, 08:33

If you have power to the fuel pump and it doesn't run then the pump itself is bad. You can install a new pump cartridge inside of the OEM assembly but I would avoid the really cheap Chinese versions.

Walbro makes a very good replacement but you need to be careful about where you buy it. Walbro is a good brand name and a good brand name brings the counterfeiters out of the woodwork like the cockroaches that they are. The only downside to the Walbro is that it is noisier than the stock pump.

...Lee