What is the underhood PTC fuse for? 30 Amp... What is the list of things I should lo

[senor honda]

What is the underhood PTC fuse for? 30 Amp...
What is the list of things I should look for that are causing it to blow?

Car runs ok, but what are all the things (-NOT included in the book) that I should look at?
Thanks.-Bob

[Oldblueaccord]

What is the underhood PTC fuse for? 30 Amp...
What is the list of things I should look for that are causing it to blow?

Car runs ok, but what are all the things (-NOT included in the book) that I should look at?
Thanks.-Bob

Im afraid i looked in the book.


only 30 amp i see if for the sunroof.

EDIT the heater on the carbs is 30 amp and so is the rear defogger.

[senor honda]

What is the underhood PTC fuse for? 30 Amp...
What is the list of things I should look for that are causing it to blow?

Car runs ok, but what are all the things (-NOT included in the book) that I should look at?
Thanks.-Bob

The 30 AMP fuse sits in position 24 under the hood, and my diagram
is attached to the outside of the fuse box.

[AWH]

The long/flat 30 Amp.fuse,shaped like a spanner, is for the sunroof only,nothing else.

Auke.

[senor honda]

Shaped like a spanner?
The fuse is one of the type that is a plastic block with 2 brass straps coming out the bottom which are held down with screws.
Are we talking about the same fuse? From an 89 carbed Accord? Factory Label says PTC

It keeps blowing and I have no sunroof. I'm not sure that my car even has a sunroof switch.
Why would it blow unless there was something else on the circuit?

Pretty often there are things on a circuit that are not listed on the factory fuse list.
Any further ideas?

The long/flat 30 Amp.fuse,shaped like a spanner, is for the sunroof only,nothing else.

Auke.

[Dr_Snooz]

Forgive my stupidity, but something stops working when the fuse blows and starts working again when you replace it. That would be the other thing on the circuit.

Unless I'm missing something. Maybe you just like checking and replacing fuses for fun?

[senor honda]

I'm forgiving your stupidity lol

I cannot tell that something stops working when the fuse blows.
When I replace the fuse, it blows again.
I have not sat there until it does blow, but I see that something is causing it to do so.
I just don't know what.

The car still runs whether the fuse is blown or not.
But I would like to fix the cause.

If I knew what PTC means, I might be able to start tracking it down.
Since PTC is a big fuse inside a plastic cube, Honda may think PTC is more important
than the small blade type fuses.

The drawing in the aftermarket manual is confusing and fuses are not numbered.
any ideas where I can find a better diagram?
The picture stuck to the fuse box does not show anything but what something is.
It does not show where the wires go to.

89 Accord 2 liter carbed?

What stops working on YOUR car if you remove the PTC fuse?

Forgive my stupidity, but something stops working when the fuse blows and starts working again when you replace it. That would be the other thing on the circuit.

Unless I'm missing something. Maybe you just like checking and replacing fuses for fun?

[Fixedit]

I’m reviving this because my PTC (positive temperature coefficient) relay starting continuously clicking/buzzing one time when I started up my 87 DX hatchback. Unplugged it and the car stayed running, but now at idle my battery light flickers on. Higher engine revs make the light go away. I figure my alternator is going out, but wanted to see if this PTC relay is the cause. But I have no idea what the heck it’s for. Also can’t find any new replacements, so the junkyard it is. Unless I don’t need it? Especially since I’ve done a weber 38 carb swap. Anybody know?

[Fixedit]

Honda part number is 39796SE0003

Part number on the one in my car is 056700 7370

[Oldblueaccord]

Wild guess but its something to do with the carb heater. The alternator excite wire is associated with the carb heaters somehow...again wild guess.

[Fixedit]

It honestly sounds like something I can remove. I wonder if running an open circuit has fried a relay it no longer uses. Fingers crossed I’ll do more researched later when I’m not selling my soul to the business I work for lol

[Oldblueaccord]

It honestly sounds like something I can remove. I wonder if running an open circuit has fried a relay it no longer uses. Fingers crossed I’ll do more researched later when I’m not selling my soul to the business I work for lol

Accord 89 form east europe(PTC problem)

if with google search thats all I gots.

[Fixedit]

Yeah that’s about all I found too, leads me to believe I’m okay without it. Funny thing is, the weird battery light flickering at idle completely stopped (I checked, the bulb is still working in the dash). iunno!

[ShiRen]

Do you even have the carb heater still installed, if not that thing shouldn't even be doing anything, thats what I find odd. I can confirm fuse 24 goes to the efe heater, section 11-11 or page 118 in my book. If its still installed you can double check it by putting the fuse back in and unplugging the heater and see if it does anything funky. I don't have my heater plugged in, it only still exists because I have the stock carb and its like permanently glued to the manifold, also if I take it off it might mess up the spacing.

[senor honda]

Do you even have the carb heater still installed, if not that thing shouldn't even be doing anything, thats what I find odd. I can confirm fuse 24 goes to the efe heater, section 11-11 or page 118 in my book. If its still installed you can double check it by putting the fuse back in and unplugging the heater and see if it does anything funky. I don't have my heater plugged in, it only still exists because I have the stock carb and its like permanently glued to the manifold, also if I take it off it might mess up the spacing.

My understanding of a 30 AMP relay is that it will carry a 30 amp load when triggered.
If it is not being used, the amps it will carry doesn't matter.

If it IS being used, then it needs a 30 amp relay.

Most relays have the same pattern of pins on the back and are interchangeable
and do the same job if the amps are the same. I look for relays from BMW's since
German relays IMHO are built better.

If the pattern of pins is not the same, I put quick connectors on some 16 GA wire
and plug them in where needed. When I have no space inside the relay box, I mount the relay nearby outside of the box and my plug-in connectors are insulated. Euro rally cars always have relays outside and accessible for quick servicing during pit stops.
Relay doesn't know or care where it is mounted.

Some relays have a diagram on the side that tells what each pin does.
I just wire them the same.
-------------------------------------

I have done a lot and got a lot smarter since my original post.
I simplified and cleaned up the engine compartment and haven't needed a carb heater for years.
....one less thing to go bad and leak.

[ShiRen]

I think Fixedit was only asking because he was going to remove it, its for the carb heater, it shouldn't be needed if he has a weber. His relay is probably bad and the control unit is closing the coil making the buzzing noise, but there is no actual load on the switched side.
Ngl, I don't think it occurred to me that this is a relay and the control box under the seat switches it on regardless of if the heater exists lol.

I highly doubt that it even carries a 30a load... I know its a resistive heater, but 16ga wire is very borderline if it does, if the heater shorted it might not be pretty.