Dual Electric Fans Not Working
 

Now that the warm weather is out, I've noticed that the water temperature at idle has gone up to approximatly 235 degree F. When the car is in motion it settles down to around 175 F. I have a drilled out 180 state and while the temperature at idle is at the 235 F mark the dual fans in front of the rads aren't working.

Any suggestions?

Where is the fuse and relay for the fans, I can check that first.?

First we need to know if you are really at 235F.... Fan turn on is around 220-227F generally... But we have seen many of the temp gages that were off... Mine looks like 160F when in fact I am at or over 180F... Its really strange... also we don't see too many cooling system failures on the Bonnevilles and other H Bodies.. Not sure what going on Frank.. We might have you car in the Bonnevilla shop for a while..lol

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Thanks for the reply jr, , for the time it's been on the road (6 months) I've never seen that fans operate, mind it was November when I started driving it. The outside temperature when the gauge was at 235 F was 60 degrees F. I would assume it would go even higher if I let it idle longer and or the outside temperature was even higher. Another thing I noted was that after idle and the temp. being at 235 F the overdrive didn't work. When the temperature went down to 175 it finally worked again.

Sounds like things are getting too hot.. The 94-95 PCM watches trans temps... If you had no OD that the trans surpassed 260F... You may very well have some cooling issues..

when you go to NEBF will you hit any traffic?

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Never been to NEBF before and Mick and I are driving alone mostly at night. I know for a fact that we'll be at the boarder at around 5:00 pm and there will be traffic for sure.

If somone can tell me were the relay and the fuse is, I can check it. I beleive the relay is a black box? Is it located somewhere on the firewall?

Frank there are actually 2 relays.. One for low speed the other for high speed.. we need to find the schematic for you..

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Passenger side relay center on firewall. There's three there I think... AC low speed and high speed.

If you turn the ac on (I know..do it ianyway) and set the temp to 60 the fans should try and come on automatically.

Thanks Don and Bill, Mick took the car to his part time job and will be home tonight at 11:00pm so I'll check in the morning. So Don, it's normal for the OD not to work if the car is overheating then? I also noticed that when I was on the highway, the OD still didn't work when the car went down to the normal temperature. The next time I drove it, it worked fine and has ever since. It only doesn't work when the car over heats.

Thanks Guys.

Yes its normal for the PCM to try to do what it can to save the trans..

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Hip Hip Hurray for the PCM, all hail to the PCM.



Hail master Hail.

Does the 95's PCM have it where if the coolant temp reaches a ceartin temp, then the computer will shut off the car?

not that I am aware of

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I believe this will identify what the relay's belong to.


https://pic4.picturetrail.com/VOL733.../248367339.jpg

I turned on the A/C and then had the heat on high and then lowest and the both engine fans did not turn on.

I took one of the relay's out for the cooling fans and there are 4 fins in the bottom. How do you check to see if the relay is working or not?

Apply ground to either 85 or 86 and power to the other while measuring for continutiy between 30 and 87 ( or 87a, whichever has the connector.)

85 and 86 create the magnetic force that pulls the switch from 87A to 87 and connects it to 30 IIRC.

I believe that's the correct way to test a 5 pin relay. I'm trying to test a 4 pin relay, therefore pin # 87a does not exist.

The only difference between the 5 pin and the 4 pin relay is that the 5 pinned ones have both a normally closed and a normally path. They are considered the universal fit relay. 30 to 87a is for normally closed and 30 to 87 is for normally open.

You can purchase the 4 pin relays in either normally open or normally closed configuration but the pins will still be labelled 30 & 87 on both kinds.

Ok here's the update, I was checking to see if there were any loose wires and this one happened to come off. I took it all apar,t cleaned up the connection and solldered it back on. I don't know if it's a temporary fix or permanent, but it had no effect on getting the fans to run again.

https://pic4.picturetrail.com/VOL733.../249289434.jpg

Next I took off each relay and switched them around and still the fans didn't turn on. I took off one of the relays, and crossed the connector wires with a pair of needle nose pliers and the fans came on for a second, I didn't hold the connection for long since it was raining out. When I did the same for the A/C relay the clutch seemed to engage and disengage, I hope tha'st a good thing since my A/C isn't working.

Anyone have any other suggestions, I'm still thinking that it might be the relay, but what are the possibilties that all 4 relays that I was switching around are gone?

It's hard to tell from the picture, but is there another wire on the connection at the lower left? If not, that wire puts those two resistors in series. I can not see the upper left either, but try running a jumper wire from the upper left resistor to the connection on the upper right one. See if they work then. My guess is that one or both of those resistors are open.

Better yet...it looks as if there may be a resistance marking on the resistors. If so, and you have a meter, check the resistance of each.

Yes, there is a jumper on the other side and it has a good connection. I need to learn more about electricity........I'll try to do as you suggested. One things for sure, both fans did operate for a split second when I was crossing the wires on the relay connector, so I'd say with confidence that the fans motors aren't siezed.


Oh my Bonne liys over the ocean.................oh how I want my ol Bonne back.

Good stuff you got here Frank. You know that you have power going to the relays, that the fans work and that the only question I see left is are you getting the ground signal from the PCM to actuate the relay and turn on the fans.

Now..here's the million dollar question. Are your temps according to the gauge accurate? Reason I ask is I fought the fans on my 1995 to find out that my gauge read higher and due to it's lying I was looking for the fans to be on when the PCM didn't want them on.

Bill, I have a drilled 180 stat and at normal cruising the temperature shows apprximately 177 degrees when I convert from Celcius. When it idles for about 20-30 minutes it's as high as 235 degrees. If the gauge is off, it's not off by much. As for the ground from the PCM, you're not going to believe this but I don't know where the PCM is located or what it stands for. I think that's the computer isn't it? Aslo when I did the test of turning on the A/C and putting in on defrost, the fans didn't tun on.


Don't I feel stupid.. :oops: :roll:

the PCM on your 95 is up under the dash above the passenger foot panel.. there are 3 connectors on it, red, white and blue.. and yes, its your car's computer

PCM stands for Powertrain Control Module

Franko... going to your relays are 4 wires. One is battery power and thick.. probably 30 or 87, the other is output to the fans.. the other of the 30/87 pair. The other two..one should have power and the last one is a trigger or the ground from the PCM to the relay to actuate it.

You can..run a switch to the high speed relay as Wren did and call it an override. That way you can turn then off and on yourself.

On what the gauge reads. Yes..low side..mine read perfect..high side there was degradation. That is why we'll test it and help you out. Meanwhile..maybe the override is the way to go.

While driving this weekend I had to shut off the engine at every traffic light to avoid the car going over 240 degrees F. Since both fans turn on when I cross over the wires on the coolant temperature sensor, I was thinking:

1. add a switch to bypass the sensor and turn it on when I start overheating and then purchase a Coolant Temp. S. at 50% off in the US at NEBF.
2. Bite the bullet and just purchase one here and change it before we leave.

I'll decide by the end of the day.

By shorting the wires..you may be telling the PCM a temp that's high enough to turn on the fans.

I'm no longer suggesting this to you Frank, I'm telling you. Wire up an override switch. Get to the US where scanners exist. We'll then find out what is wrong, fix the correct part or adjust your way of thinking about your temp gauge if needed.

Don't spend another dime on the fans until you are here.

Well, I must say, when BillBoost37 changes for a suggestion to a "I'm telling you" then past history dictates.......Do It. With that being say...............Yes Sir! Got to search for some 18 AWG wire, couple of connectors, one switch and an electrical 101 book.


I must say that I like the sound of "Don't spend another dime on the fans until you are here."

I'm working on boosting the US economy. 8)

Clean that room til you find the stuff you need. Then rig this up. Any questions..either post here or refer to the WillWren post .

I'm not allowed to post here since I've been sentence to the tool room for the day. I'll have to post later one. Siga..................Friga....................... do.


Bill, I swear when I post pictures of the before and after, you'll know I did a lot of work cleaning up.


Ok........I'm off.

Wait a minute......if you're going to do an override, let me steer you in the direction of the PCM wiring harness instead of sending you through the firewall to the relay.

That's how I did my SSEi the last time. Much better, easier wiring, same effect. If you want to do this, send me a PM to remind me, and when I get home, I'll give you the exact wire to tap into on the PCM wiring harness, including taking a very detailed pic of it on my 95. I have no hushpanel installed right now (awaiting a new airmix actuator), so it's perfect timing.

Please note that this is for 94/95 Bonnevilles ONLY:

Remove the passenger side hush panel. Pull the CENTER WHITE connector. Blue on the left, red on the right, white in the center:

Attachment 48847
In this pic, the rear of the car is TOP, the front of the car is BOTTOM, the driver's side is LEFT, and the passenger side is RIGHT. You're looking UP, facing forward.



After you pull the connector, you're looking for a dark blue wire in slot D10. One side of the connector ONLY will have a blue wire in hole #10. In these pics, if you look at the top row (not marked, but not the C side), you can count from left to right 1-whatever. My thumb is next to slot 1.
Attachment 48848

Attachment 48849

Attachment 48850

Provide an ALTERNATE ground through a switch for this wire. Don't cut it and leave it dangling on either end. Tap INTO it, providing another path to ground through a switch. When you turn the switch on, the fans will come on high.

Will, thanks so much for the great write up.

Now just so there's no misunderstanding since if I wire this up wrong, I'm not going to NEBF due to the fact that the Bonne probably won't start.


I tap into the dark blue wire in slot D10 (the wire that is actually touching the grey plastic clip on the white connector to the PCM. (see picture below) I'm taping into it with the Blue splice connector on my white wire (I've supplied). I must NOT cut D10. since it must remain one solid piece. My white wire continues to a switch and the other side of the switch (black wire) goes to ground.

What the switch is actually doing when turned on is supplying ground to D10 (dark blue) wire on the PCM.

Once installed and the switch is turned on, both cooling fans will turn on.

I will place electrical tape at the end of the switch so as to not have exposed connectors.

Is all this information correct?

D10 is the raised dark blue wire, it has an empty slot to the left and green wire to the right
https://i14.photobucket.com/albums/a...n/DSC04028.jpg



White wire taps into D10 (dark blue wire) on PCM
https://pic4.picturetrail.com/VOL733.../251105019.jpg

Black wire to ground on car.
https://pic4.picturetrail.com/VOL733.../251105026.jpg

You got it, bud. Dead on.

But you're actually grounding the high-speed fan RELAY just before the PCM does. Giterdun!

The extra switch that I already had in the tool room has an extra prong, would that have been used as a ground wire? In other words, it's to ground out the switch?

Do I need to ground out the switch as added protection?


The 3 prongs would have been:

Left----- Power in
Middle---ground
Right-----Power out

Put the ground on the center lug. Then put the tapped PCM wire on either of the other two, depending on which way you want the switch when it turns the fans on. ;)

Just plug it in and test it. You'll get it. :D

Alrighty...

Are ya done yet? Looks like you are ready to come into the US with fans a blazin!

Yes I am done Boosty and it works.

Willwren, thanks so much for the detailed explanation, it was perfect. I still need to get the fans working on there own but at least I can make it to Boosty's crib without the Bonne overheating...........I hope. Will, do you have one of these hooked up in your car?

Both of my cars are overridden, and my SSEi stays on high all summer long. Day and night. They turn off just before launch at the track to save loading the alternator.

The 93 is wired into the PCM harness similar to what I just had you do. The SLE is wired through the firewall to the relay. I hooked a couple of these up for Matt and John at WCBF 05 as well.

Glad you goterdun. ;)