Heater resistor fire - 1986 2.9 4wd

[beerhunter]

Hiya
So..... I was merrily driving along the motorway, when I smell burning - and then BILLOWS of smoke come through the air vents. I pulled over and ripped the connector off the resistor (it had already started to fuse itself together), and luckily it didn't get any further than that. I have read of other people having this, and it likely being an accumulation of debris in the motor housing.

Anywho, I need to yank the housing and heater core out to check it all over, and see what needs replacing (resistor and plug for definite! Will have to see if the blower and wheel survived). In the meantime, I am intending to simply connect the two water pipes that go in to the bulkhead/firewall (on the left of the housing) to each other, so I can continue to use the truck (minus heater and blowers) in the meantime.

Am I overlooking anything to mean this is a bad idea/won't work? Assuming it's a sound idea, does anyone know the internal diameter of those pipes, so I can source a suitable temporary connection?

It shouldn't take too long to fix, but I need to order parts from the US to the UK, so it will be a few days at least.

Many thanks

 

[Uncle Gump]

I don't think you even need to bypass the heater core. Just leave the hoses connected.

Pull the blower motor and check for debris.

 

[beerhunter]

Thanks - I was assuming worst-case scenario that the core may be damaged too.

 

[Josh B]

There's a little contraption on mine apart from the blower motor, just under the hood kinda between the heater housing and the firewall. I think it's only a couple screws that holds it on. Inside are some small coils that heat up, I'm not sure what they are.
Debris can get in there and pile up until it is touching those electrical coils and possibly catch fire

 

[Curious Hound]

Inside are some small coils that heat up, I'm not sure what they are.

Those are the fan speed resistors being discussed.

 

[Josh B]

Yeah, I realized after posting that

 

[beerhunter]

There's a little contraption on mine apart from the blower motor, just under the hood kinda between the heater housing and the firewall. I think it's only a couple screws that holds it on. Inside are some small coils that heat up, I'm not sure what they are.
Debris can get in there and pile up until it is touching those electrical coils and possibly catch fire

Hi, thanks all for the replies. Yes, that it the little b... monkey that caused the trouble. Assuming it's not raining at lunchtime I will get outside and start pulling bits off... RockAuto list both the reistor and its plug, so I just need to see if anythign else needs replacing too.

Thanks again

 

[Josh B]

Did you clean out the little area where it mounts? I had to go into or under the dash to get all the crud out of mine after some little varmit got into it. It has been a long time so I don't remember all the details but I closed every port of entry I could find with a screen wire

 

[James Morse]

When I did mine, I had to do the pigtail as well. That was on the '99 so might be a little different for previous gen.

Kind of interesting because other half's Lexus RX300 seems to smoke and/or bad smell somewhere by the firewall, but it's intermittent, like, she went to store, all good, but told me just as whe was pulling in home it did it again. Last time she showed me, I looked at it, couldn't figure out where it was coming from, turned it off, restarted, it went away. I'm wondering if it has anything to do with heater resistors but I've never heard of them smoking unless there's a short somewhere they usually just burn out and you get only high fan speed. Pretty easy fix on the '99, hope it's easy for you.

I have so many projects I'm not about to start being the fix-all for the Lexus (263k miles). But if it's something simple/easy I'd do it.
I think it wouldn't be a bad idea for her to lose the Lexus and her '09 Rabbit (good mechanically, but trashy body) and get something newer.
On the other hand Lexus is pretty nice, so if it can keep running that's probably a lot cheaper than newer. She's had it on a few 1000-mile trips and it was fine.

 

[beerhunter]

OK, so... Good news is it was just leaf litter scorching on the resistor. There was loads of charred gubbins that started dropping out when I started disturbing the plastic casing.

The bad news... D@MN it's tight under there! Mine has A/C and all the associated stuff for that means I can't pull the housing all the way out, or even separate it whilst still in the engine bay.

How can I safely depressurize it so I can pull bits off? I can't take it to a shop as it is now in pieces.

And is the A/C a separate system to the engine cooling? It appears to be, but I don't want to cause issues on a truck that currently never overheats.

 

[85_Ranger4x4]

The heater hoses will probably need to be removed to get the evap housing out.

If you are careful you can remove the entire A/C system without opening it up. One side of the evap housing will come off so you can separate it from the evaporator.

I made this awhile ago that might help:

Cowl Cleanout

Original Poster: Difficulty: 2 out of 10 Time to install: Disclaimer: The Ranger Station.com, The Ranger Station.com Staff, nor the original poster are responsible for you doing this modification to your vehicle. By doing this modification and following this how-to you, the installer, take...

www.therangerstation.com

 

[beerhunter]

Thanks for that. The pics are very useful.

You mention a bolt from the inside - does that hold the whole condenser case to the firewall? Or does it retain the right-hand (if stood looking under the hood) piece of casing?

I was working solely under the hood.it seemed like it was ready to come (barring the lack of room), but I wouldn't be surprised if I had missed something.

Thinking about it, I think I may have enough room to pull the whole thing forward if I pull the alternator.

 

[85_Ranger4x4]

It holds the main housing, even my non-a/c box had it.

There may be some variance through the years though.

 

[Josh B]

I went in under the dash with mine, I haven't seen 85_Ranger's write-up yet but intend to shortly.
I used a shop vac with a sharp shooter end on it to get as much out as possible.
While under the dash and when re-assembling the system I closed every entry with a good screen wire using little pancake head screws from sheet metal work to fasten it

 

[Josh B]

OK, that cowl, I was thinking about the inside heater ducts. I had to do that on my 87 once