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I'm wanting to try the modification to manually activate the fans via a switch, but have run into a problem and am hopeful someone has an answer or idea. I wired one side of the switch to a solid ground and the other side to the brn/red wire on the fan relay. When I turn the key on and throw the switch, the fans do in fact come on. However, if the bike is running and I throw the switch, the bike shuts off. Any thoughts?
 

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GL1800 Doctor
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You are grounding the ECM's control line to the relay. Not a good idea. Computers don't like their output lines shorted to ground. You will need to wire it so the ECM is disconnected when the ground is applied to the relay.
 

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Thanks techdude. I have read a few entries on this forum where folks have indicated they have done this modification basically the same way I did and it worked. Also, doesn't the ECM apply a ground to this same lead to activate the fans?
 

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I do not understand what your mod will accomplish in regard to improving the cooling system. The problem with parade mode over heating occurs ONLY when the fans ARE running. At that speed the fan created air flow counters and nullififes the natural air movement induced by the forward travel of the bike. Thus, the better fan switch solution would be to place a switch to turn the fans off during those conditions and then at least have teh forward motion related air to flow through the rads. What am I missing here?

prs
 

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GL1800 Doctor
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It does supply a ground, but that is accomplished by turning on an internal transistor or gate. Applying a ground to this gate is not the same as it applying the ground from within. Pigeon Roost has a point about the fans. Reversing the fan direction, the blades, and then using the manual switch will help at certain speeds.
 

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Discussion Starter #6
Appears I may have misread or misinterpreted the issue. I'll go back and read the "overheating" threads again. It's nice to have a place to get some help. Thanks guys.
 

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I'm wanting to try the modification to manually activate the fans via a switch, but have run into a problem and am hopeful someone has an answer or idea. I wired one side of the switch to a solid ground and the other side to the brn/red wire on the fan relay. When I turn the key on and throw the switch, the fans do in fact come on. However, if the bike is running and I throw the switch, the bike shuts off. Any thoughts?
I too have read several posts of people doing the same mod the same way with no problems. But IIRC the 2006 and later models have a different control circuit. What year is your bike?
 

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I did this same mod on my '03 with no problems, it should work on all models up to and including '05, from '06 onwards the wiring is completely different.
I don't agree with Pigeon Roost's comments about the overheating only occurring when the fans are running, the only times my bike started running really hot were in that zone from 15mph up to about 20 or 25mph when the fans are NOT running, they only work up to 15mph.
Since doing the mod if I get into that situation again I switch the fans on for a while and the gauge drops, then I can switch them off again.
 

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I don't agree with Pigeon Roost's comments about the overheating only occurring when the fans are running, the only times my bike started running really hot were in that zone from 15mph up to about 20 or 25mph when the fans are NOT running, they only work up to 15mph.
Since doing the mod if I get into that situation again I switch the fans on for a while and the gauge drops, then I can switch them off again.
No problem-o in disagreeing with me. I admit freely that I have NOT tried the manual fan switch modification. I can say that my bike pushed its temp gague into the higher regions (I won't even say over-heated becasue it never did spew) only when the fans were running and the forward speed of the bike was such that the air flow from foreward travel nullified the opposing air flow created by the fans.

Steve; do your fans push air rearward and thus increase the air flow at modest speeds? The OE set-up in the USA has the fans pulling air FOREWARD, thus at speeds at or over about 15mph, the fans would actually reduce effective air flow -- unless you are riding backward. But, if it works for you and you are happy wit it, grrrreeaaattt!

prs
 

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No problem-o in disagreeing with me. I admit freely that I have NOT tried the manual fan switch modification. I can say that my bike pushed its temp gague into the higher regions (I won't even say over-heated becasue it never did spew) only when the fans were running and the forward speed of the bike was such that the air flow from foreward travel nullified the opposing air flow created by the fans.

Steve; do your fans push air rearward and thus increase the air flow at modest speeds? The OE set-up in the USA has the fans pulling air FOREWARD, thus at speeds at or over about 15mph, the fans would actually reduce effective air flow -- unless you are riding backward. But, if it works for you and you are happy wit it, grrrreeaaattt!

prs
PRS,

The cooling fans TURN OFF at any speed above 15 mph (Give or take 1mph)... All GL1800 Cooling fans push the air forward as designed by the factory. The fans do not contribute anything (Good or Bad) above 15mph, they have been turned off by the ECM.

The problem is insufficient natural air flow between 15mph and about 25 mph. After about 25 mph there is usually enough natural air flow from the vehicle moving forward to keep the GL1800 operating nominally temperature wise.

The theory of turning the fans on manually is the air flow created is sufficient to cool the radiators even though it is counter to the natural airflow coming in.

The best solution is to correct the wrong way air flow of the fans and let them come on when ever additional cooling is required.

Then there are those that believe they and everybody else in the world do not have this problem and we are obviously making it all up...
 

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PRS,

The cooling fans TURN OFF at any speed above 15 mph (Give or take 1mph)... All GL1800 Cooling fans push the air forward as designed by the factory. The fans do not contribute anything (Good or Bad) above 15mph, they have been turned off by the ECM.

The problem is insufficient natural air flow between 15mph and about 25 mph. After about 25 mph there is usually enough natural air flow from the vehicle moving forward to keep the GL1800 operating nominally temperature wise.

The theory of turning the fans on manually is the air flow created is sufficient to cool the radiators even though it is counter to the natural airflow coming in.

The best solution is to correct the wrong way air flow of the fans and let them come on when ever additional cooling is required.

Then there are those that believe they and everybody else in the world do not have this problem and we are obviously making it all up...
Paul;

I mostly agree with Ya.

Have you tried running the OE fans manually switched in the OE direction? I do not know exactly at what speed the fans' air flow is, but it seems to be pretty close to an equivalent 15 to 17 mph speed at which my OE fans turn off. My bike's previous tendency to heat-up DEFINITELY occured only while the fans were still running and the bike at slow parade type speeds; NOT at speeds above which the fans cut off.

Maybe I am wrong, but I "think" it would be generous to estimate the fans create an equivalent "reverse" air speed of 25 MPH. If the fans shut off at 15MPH forward bike speed; then at any speed above 10MPH the fans would be counter productive. Now, if the OE fans are far more powerful than my thinking allows; say they pull an equivalent air stream to that of a rearward travel speed of 35mph, then I can see a small margin of speeds where the fans would minimally contribute if operated beyond the OE speed tuning. But, to generate that much force at both fans, I would think the load put upon the alternator would demand more engine load and thus generate more heat than the fans cooling could balance.

I think your way of going about it, reversing the fans' blade pitch and direction is one better way to go. For me, using a more heat tolerant coolant seems to do the job adequately; but I do not live in a congested, hot area. Thank God I'm a country boy!

prs
 
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I reversed the fans some four years ago and last year decided to also add a manual fan turn on for the rare time I would be at high altitude with a 20 mph wind at my back - I have only turned on the fans once so far but the activation was done by locating the fan relay (under the seat) and I set the switch to activate the relay not the fans directly.

To be honest the manual turn on is not really needed if the fans are running in the correct direction but it does serve to cover all the bases I guess.
 

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GL1800 Doctor
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I'm wanting to try the modification to manually activate the fans via a switch, but have run into a problem and am hopeful someone has an answer or idea. I wired one side of the switch to a solid ground and the other side to the brn/red wire on the fan relay. When I turn the key on and throw the switch, the fans do in fact come on. However, if the bike is running and I throw the switch, the bike shuts off. Any thoughts?
You should cut the control wire from the ECM, use a SPDT switch and connect the fan relay wire to the center lug, the ECM wire to one of the outside lugs, and the ground wire to the other outside lug. This will ground the relay in one position and connect the ECM to the relay in the other position. This will keep the ECM from ever seeing the external ground being applied to the relay. :thumbup:
 

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Two problems?

Howdy...
Seems to be two heating problem areas within Honda's grand design of keeping the bikes happy. As for me, I went for the replacement fans from the company touted by several strings on a couple of posts herein and so far works fine (sounds like a couple of copters hovering overhead when you are stopped)...HOWEVER, and there's usually a however: the problem now is that nasty parade area between (on my bike) 17 and 27...sucker get's a bit warm...SO, he said making a long epistle longer: I seem to recall someone posted an actual diagram sometime back on just how to install the much sought after manual fan switch complete with simplistic instructions and pretty lines drawn everywhere. Anybody remember who and where?
 
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