Lowrance Hook 7 Help

Any Lowrance guys on here? My Hook 7 will not turn on. Cleaned corrosion off connectors and the circuit board has zero corrosion/salt looks brand new still. Any help or guidance is much appreciated.

There are a lot of things that can go wrong. Here is what you need to check.
- is the battery good? Confirm it to run with another FF.
- check fuse
- check if battery still hold voltage 12-ish volt under load.
- if all above are good, you have a bad FF.

The first step should always be to test your fish finder (and your wiring harness) on a known to be good battery before concluding your unit might be bad.

If it starts using a different battery, and assuming your battery shows at least 12 volts when freshly charged, test the amperage it's delivering. Most batteries can hold a 12 volt charge under load while delivering nearly zero amps, and there's a spike in demand for amperage, not voltage, at start up.
 
If amps at the battery look good, test the amps being delivered to the head unit plug. Corrosion within the wiring between the battery and the head unit can significantly reduce the available amperage long before it effects the voltage.

There've been more than a few "it suddenly won't start" problems that were traced back to insufficient amperage to meet the demand.
 
Good luck.

Thanks guys! I took it to bass pro and asked if I could plug my unit into their display setup and it fired right up. I will be in search of a new power cable.

Amazon carries them for about $30.  Don't let the blue plug throw you off, this is the one I've been using on my HOOK-7 for a year.  I posted the part number for the cable with the red plug, but can't locate it now.  Duh!

https://www.amazon.com/Lowrance-3005-6833-Power-Cable-Hds/dp/B002BBGOG0/ref=sr_1_3?ie=UTF8&qid=1523747240&sr=8-3&keywords=lowrance+power+cable&dpID=41h9%252Bt9zjoL&preST=_SX300_QL70_&dpSrc=srch

Thanks! So this will work for the power side? Just use the power and ground and chop the rest or zip tie?

Personally I would not throw away the Lowrance cable just yet.
There is way to clean the corrosion and die electric grease, it will be able to work again.
Here is the deal- If you can bring it down to Santa Clara, I am willing to spend time on it.

Go with Chet's offer if you can.

I cut the NEMA part of the cable down to ~4 inches long - I'll never need it on a kayak - then dab a bit of liquid electrical tape on the end where I just cut it, use heat shrink tubing cut about an inch too long over that, fold the excess heat shrink over and put on another piece of heat shrink and figure if water can get through all of that, I deserve any problems it might cause.

Then again, I over-think everything (and I got a heck of a deal on a big pile of marine heat shrink tubing).

Personally I would not throw away the Lowrance cable just yet.
There is way to clean the corrosion and die electric grease, it will be able to work again.
Here is the deal- If you can bring it down to Santa Clara, I am willing to spend time on it.

Thanks Chet! I ended up just ordering a new cable off EBay for $30

BTW the Lowrance part number for the cable that came with the unit, with the RED plug is
000-14041-001.

BTW the Lowrance part number for the cable that came with the unit, with the RED plug is
000-14041-001.

Thanks! I found it after a little while with google haha. Thanks for all your help!