No heat, mid winter.

[TheChimera]

So my heater went out today, while it was -45 degrees. The fuse isn't blown, still need to check the electrical connections, but the Fan On-Off switch is useless and the other controls don't do much. Any ideas on where to start? 1987 Ranger 2wd 2.9L manual non-A/C. Please, any input helps. PS, engine doesn't currently have a thermostat, but heat was working without it before this morning.

 

[black_demon69]

First off I would put a tstat in then I would check the blower switch and resistor then motor and wiring.

 

[pocket-rocket]

I second the tstat. It limits the amount of coolant going through your radiator so it doesn't get cooled off so much that the engine can't fully warm up.

I know on my Ranger the harness where it plugs into the blower motor resistor had melted from a nasty corroded connection to the resistor, so when I bought a new one I cit the connector off and put insulated spade terminals in its place. I also put a dab of dielectric grease in each one and haven't had to touch it for about 4 -5 years now.

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[20yearredneck]

Original fan motor?

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[bigmark303]

I would get a thermostat in there asap. Temperatures that low and no thermostat is just bad for the engine in a few ways. Engine needs to heat up to run in closed loop mode at its most efficient.

I run no thermostat in the summer for my rally vehicles. Pedal to the floor all day in 60-80 degree heat and they never fully heat up or throw any kind of heat out the vents. I cant imagine no thermostat in the winter 30 degrees and below. Engine would never heat up and run very lean from the dense air in a cold engine.

 

[Mark_88]

I would also say its the blower motor itself...the resistor will allow full on even when toast...unless it has deteriorated completely...

Mine went on me last fall and they are very easy to test...just plug it in to a 12v source and the fan should spin...if not...replace the blower...

Good thing is they are pretty much the same throughout 1st, 2nd, and some 3rd gen Rangers so getting one from the junkyard or even buying a new one is still possible...just remove the old one and compare it...my last one came from a 93 Ranger...doesn't matter what engine or other options...even A/C equipped use the same fan.

 

[fyre82]

2.9 heaters get coolant directly from the heads, that is why they normally warm up relatively quickly. So you should have some heat when you are moving. If there isn't even that, there's more to the story like a clogged core, kinked hose, etc.
I concurr that if nothing comes out from the fan then look at whats been suggested.

Good luck
Rich

 

[Kowboy]

I would think that -45 degrees would certainly test anything that was marginal.

 

[TheChimera]

Gremlins

Must have been the extreme cold, cause the control panel started working again today. Will be putting in the thermostat after work today, but picked up heater core, hoses, blower resistor and control valve just to be safe and cause I'm sick of chasing these little problems. But I can't seem to locate the OEM control valve. Didn't see anything looking like the incoming part on the thermostat housing, water pump or along the lines. Attached to the core? If it needs a vacuum reference, shouldn't it be underhood near the heater plenum? The only things attached to my vacuum tee are the brake booster, EGR and fuel pressure regulator.

 

[kunar]

No control valve on those heater cores. They get coolant all the time.

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[Mark_88]

An 87 doesn't have a vac control as far as I can recall...that was introduced later...the second gens had some as my 92...but prior to 89 they were all cable controlled...unless someone had 'upgraded' your truck previously.

If your heater blower is working and there is heat coming out I wouldn't even change the T-stat for now because that was not the problem...unless the heat was very weak.

My fan would work if I tapped on the end of the blower motor...for about a week or so...it was a corroded connector inside the fan motor case and may have been something I could fix...except for what it was worth as opposed to simply swapping the whole motor.

They tend to get moisture up inside and that just messes things up over time.