JoshToy84

Ok so I was reading the Heater thread for the 4 runner, but wasn't sure how much of it applies to my truck. So I'm having a heater issue.

For one, my controls are completely jacked up (if anyone has a control panel with sliders and AC switch let me know). I'm able to slide the control, but as I slide it more towards heat, I feel tension until it snaps all the way to full...obviously broken. But I still get very little heat from it. And the fan seems to only run on high. The first two steps don't do anything.

Second, I've noticed that my temp guage doesn't go much above C. Reading the other thread suggests that the norm temp reading should be about in the middle. What might it be? Faulty temp guage, temp sensor, or a more serious issue?

XtraSlow_XtraCab

ISSUE 1- CONTROLS:

On the 84-88 trucks, those slider arms pivot on a black plastic frame and are retained there by cheapo white clips. If there is too much resistance in a cable, these white retainer clips are the first to snap. Thats why in 1989, they got smart and went to steel rivets or some other design... I don't quite recall what the initial solution was. So, go to a junkyard and find a few white clips. They're different sizes so I would just nab all of them on one heater control panel.

But first, remove all of your heater control cables. If these have been removed and reinstalled prior to, then they may have been routed incorrectly and are now binding. They're very finicky. OR, the water valve munted on the firewall could be cranky and THAT is the ultra-high resistance that broke your "heat slider pivot clip." Regardless I would make all of the inspections listed AND lube the cables anyway for maintenance purposes. Some spray can silicone should work unless you want to get messy and give them an oil bath

The low settings of your fan run through a resistor pack. Dorkheads over at AISIN or whatever 12 volt electronics manufacturer of the time did not bother to seal the resistor coils in a casing, thus they were exposed to elements and very few work anymore. Your HIGH setting works because it does NOT utilize a resistor. The motor is pulling maximum amperage. This unit can be found screwed into the duct work or blower motor housing (I forget which) below the glvoe compartment and retained by two self-tapping screws. It has a rectangular plug with 3 or 4 wires in it. Feel free to order another one (35 bucks I think was the going rate?) but the fans are already underpowered so I see no need. I personally am content with on/off.

ISSUE 2 - TEMP GAUGE:

The factory location for an 84-88 temp gauge needle on a factory-running 22R (195deg F) will be JUST UNDER half. About 10 degrees below half. The only time that my truck ever reads half is on long, steep grades. Typically, dashboard instruments on ANY VEHICLE are the last to blame (minus the oil gauge on these, but those were crap from day 1).

I point the blame at your sending unit, or the wiring in between. The temp sender wire goes through a waterproof, green plug which are difficult to disconnect. Often people screw up and split a wire at this connection while using all of their might to disconnect that green plug. So... the temp sending wire could be frayed at that particular location causing too much resistance and giving you a low reading.

But start with the sending unit first.

JoshToy84

Now that you've explained that, it would seem that that's exactly what's happened. I failed to mention that as I slide it more towards heat, the arm actually starts to turn to the right.


Yeah, $35 for the conveinience of 2 lower speeds...nah. I hoped it might be a cheap fix. I think I can live with it.

I kinda figured it might be the temp sensor, just wasn't sure as it seemed the 2 problems might be related. Maybe it would be worth spending $35 on one of those IR Temp sensors. Might be worth having around just in case.

Thank you so much for this great info. You've saved me several hours of troubleshooting. And a ton of frustration.

The only problem is that Toys are few and far between in junkyards around here. And the ones that I find are nearly stripped. At least the trucks are. Not sure if the heater controls for another year or model would be compatible.

Rich849

Once your controls are working if you still dont blow hot air your heater core could be plugged.My 85 had to be replaced nice and hot in the snow now.Lots of work though.