temperature indicator light and sporadic fan

[atxvalk]

I ride daily in stop and go traffic in Texas. This summer i have been having trouble with the temp light coming on and an associated non-functioning fan. Granted that when the fan is operating the light doesn't come on, the way it should be operating. Sometimes the fan comes on and sometimes it won't. Also, sometimes the light will blink rapidly and then go off until it comes on and stays on. THis seems like a temperature sensor/fan activation switch issue. Usually, if i turn the motor off and then back on it seems to work again for awhile. Help! What is this issue?

ßI should mention that it is '99 tourer w/34K miles. The motor is justifiably hot when the light comes on, does the indicator unit that i have seen mentioned elsewhere having any control over the fan activation?

[R J]

Do a search on (FAN), and you will get a ton of reading material on this same topic.

If memory serves me correctly I kind of recalling it was a sensor under one of the radiator side covers.

Don't hold me to that now, as my old brain don't remember like it should anymore, too firkin OLD.

[indybobm]

On 97-99 Valkyries, the temperature sensor activated the temp light in the tach by way of a module that is behind the left side cover and coolant overflow bottle. This caused the problem you are describing in many bikes. On later bikes, Honda used a different temperature sensor that went directly to the light in the tach. The Honda service manual has a procedure for checking this circuit in 97-99 Valkyries to determin what is malfunctioning.  There is also a write on this board describing how to use the later model temperature sensor and what wiring changes to make.

This could be the problem or it could actually be overheating.

Make sure it is NOT overheating!

If it is caused by the fan not coming on when it should, then that is a different problem.
Some people have had a problem with the radiator not being grounded to the frame. That is where the fan gets it's ground to turn it on.

[F6Dave]

The temp light and fan use different sensors.

On early Valks the flickering light is often caused by a bad indicator unit under the left cover, but that doesn't seem to be the case based on your description.

You might want to get one of those infrared thermometers and take a few readings.  I bought one at Home Depot for less than $40, and it even includes an electronic tape measure.

[atxvalk]

Thanx for the responses, is the infrared thermometer accurate enough to read the temp? I assume you measure the temp of the block/heads? I have seen that the high end of the acceptable temp should be around 250, is that correct? Would it wise to go ahead and replace the indicator unit or make the change to the new style, because they are showing a tendency to fail? I noticed today even at 80 degrees on the way in to work i was getting the light to come on between fan runs, this is getting me worried!

[F6Dave]

The infrared thermometers are pretty accurate.  The problem is you're reading external temps, so you might need to take a few readings and post them here to get comparisons.

The indicator unit is inexpensive and very easy to install.  They are a weak point, but from your description it may be working OK.

[Black Dog]

Just posed this reply a few days ago, on another 'Hot Light' question...

The 'Search' function of this board is your friend 

------------------------

I've had the same problem for a few years...  My '97 Standard would have the 'Hot' light flicker, at just about the same time my fan would kick in.  Checked along side another Valk, with one of those temp guns, and found my cooling system working just fine...  Fan was working just as it should, but kept getting the 'Hot' light.

Don't know who it was, but someone posted on the Tech Board, that early Valks (I know the '97, for sure), had an extra part as part of the cooling circuit, called an 'Indicator Unit'...

Here is the part number (I ordered mine from Dillon Brothers).  Don't know what year you've got, but use the part number, and see if it matches a part for your year Valk.

Order:
Qty.    Part Number    Price Per Item    Special Order    Product Name
----    -----------    --------------    -------------    ------------
1    38710-MZ0-003    $50.99        No            Honda - INDICATOR UNIT

It is located behind the right side cover, and is a 'plug n play' deal.

Fixed my issue, and if you have an earlier Valk, should fix yours.

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Black Dog

[Mr.BubblesVRCCDS0008]

You can run a wire from the fan sensor to a ground and control it with a toogle switch to kick fan on and off as needed until you find your problem. I kick my on early in heavy traffic to help stay cooler in the Texas heat. The sensor will etill kick the fan on if you forget or don't want to kick it on early.