# Airmar P79 Not Reading



## jmrodandgun (Sep 20, 2013)

You might need a priest and small little cup of antifreeze to trouble shoot this problem. Sometimes the fluid leaks out of these. Regular off the shelf Non-toxic propylene glycol is what you need if the transducer is empty. Should be easy to tell if it's dry. Also if you go from Garmin to Simrad you might need this pig tail.


----------



## jay.bush1434 (Dec 27, 2014)

Does it read at all, like it is trying to get a reading or like no signal? If it seems like it tries to read, check that your unit is set to 200khz and not 80khz or whatever is the low frequency. If you aren't getting any signal first check the fluid level is completely full. As mentioned above, use propylene glycol antifreeze. If nothing after those checks, it is likely the transducer. They are only $80 or so but still very frustrating.


----------



## rkmurphy526 (Jun 9, 2018)

jay.bush1434 said:


> Does it read at all, like it is trying to get a reading or like no signal? If it seems like it tries to read, check that your unit is set to 200khz and not 80khz or whatever is the low frequency. If you aren't getting any signal first check the fluid level is completely full. As mentioned above, use propylene glycol antifreeze. If nothing after those checks, it is likely the transducer. They are only $80 or so but still very frustrating.


I'm going to be honest...I thought the antifreeze thing was like one of those jokes where you tell your wife to go buy blinker fluid.

Either way, I messed with it some today. Disconnected some wires, reconnected, checked connections. I then noticed that the transducer was faintly ticking, which Google informed me was a good sign that it was working. I'll get it out on the water and see if she's working now. Stand by!


----------



## rkmurphy526 (Jun 9, 2018)

So it’s still not working. Any step by step instructions on how to check the fluid? A video would be awesome.


----------



## rkmurphy526 (Jun 9, 2018)

rkmurphy526 said:


> So it’s still not working. Any step by step instructions on how to check the fluid? A video would be awesome.


Quick update...is this thing even installed correctly? There’s no place to remove the transducer from the hull without pulling it away from the silicone or fiberglass. The top cap comes off, but there’s really no purpose to it currently. It’s just the “puck” underneath the cap, which is adhered to the deck.

There’s definitely no issue with the wiring. The unit gets power and is “ticking”. Just no read.


----------



## Water Bound (Dec 12, 2018)

I’d say no, it’s not installed correctly. 

I just installed a similar ducer from Lowrance for my Go7. It does not have the fluid component, but is a “shoot-thru”. My install specs said it would not read thru the foam core of the hull, which I found to be true as I tried to epoxy it to the inside of the skiff with no modifications. It didn’t work, zero readings, and probably what yours is doing. 

I had to remove both the inner fiberglass skin and foam core, then reinforce with fiberglass the outer skin from the inside, then epoxy it in place.

All said, it now works amazingly well! Holds bottom up to 30 mph!


----------



## rkmurphy526 (Jun 9, 2018)

Water Bound said:


> I’d say no, it’s not installed correctly.
> 
> I just installed a similar ducer from Lowrance for my Go7. It does not have the fluid component, but is a “shoot-thru”. My install specs said it would not read thru the foam core of the hull, which I found to be true as I tried to epoxy it to the inside of the skiff with no modifications. It didn’t work, zero readings, and probably what yours is doing.
> 
> ...


Great info. I read the same about cored hulls. That’s more of a project than I want to get into. I’m going to most likely get a transom mount unit.


----------

