absolutley no heat...

[MardyDelica]

hi,Artacoma and other,
pls call me maybe i can help
cheers;
mardy

[jaggedfish]

I have noticed in the past that if the coolant level is low in an L400, the engine will still circulate the coolant and stay cool but the heater will not provide heat as it is dependant on proper coolant levels. The reasons for low coolant are plenty but before you do any major work it is best to check coolant level, top up if necessary and run up to temperature and see if this makes a difference. If it does... keep a close eye on coolant levels and search for bigger problems if the level drops significantly again.

If a thermostat doesn't open it is either malfunctioning which would cause the engine temps to get high or the engine temp is not reaching the temp the thermostat is rated for. High engine temps are obviously bad but a closed thermostat with low temps is not - that's how they are designed to run... the coolant only circulates when the engine needs to be cooled.

I prefer to try a simple, inexpensive diagnosis before jumping to any conclusions that could cost a lot of money and have no result or short term results.

[Artacoma]

I prefer to try a simple, inexpensive diagnosis before jumping to any conclusions that could cost a lot of money and have no result or short term results.

unique thinking there

[MardyDelica]

Artacoma;
did you say you change your thermosthat agin,
i just put new thermsothat on you l400 when you buy from me.
i dont used used one.
not all less heat inside cause thermosthat failure not on L400
i never have thermosthat problem in L400 since april of 1994 when i have my frist L400
diff design, much better
even you change new one you are not sure you fix the problem
coomon problem is thru the vent from aheat air to cold air
check this pls
cheers;

[Artacoma]

I Got Heat!!!!!
The motor that is controlled by the TEMP up and down switch wasn't working, to access it a bunch of lower dash panels and duct work has to come out and then you need very small hands and stubby screwdrivers .
I found the motor was getting power so I took it out and gave it a stern talking to.
Then I took the cover off and there is a multitude of delicate copper arms that rub on contacts on a circuit board.
A little more finger waving mixed with colourful language and I reassembled the casing and hooked it up to 12v power supply and lo and behold it started dancing like a little robot.
So reassembly back into the van with a not unreasonable number of screws left over and I have 60c at the vents where I had 18c 5 hrs ago.
If it crapps out again I'll toss the motor and replace it with a manual cable control.

[madmazda]

my coolant appears to be good and i have a manual temp adjustment so thats not the problem.... next week was going to do a pis cleaning of the coolent system and lets hope that works....

[MardyDelica]

good job rik,
as i mention to you this morning usually this is the problem, glad that i can help
enjoy,
cheers;
mardy

[psilosin]

Nice work Ric and thanks for posting pics to make the job easier for the rest of us.

Looks like another item to add to the ever growing list of flaky electronics on the L400.

[Profister]

This is one of the reasons why I drive a Chamonix. Keep it simple!

[thelazygreenfox]

guys
In Cache Creek at -5 deg C the front heat vent produced only 60 deg F temp after 1/2 hour at normal engine operating temp . I rechecked the temp enroute to Coquitlam and +3 deg C. If the o/s temp was above freezing the vents give off lots of heat but below freezing is a problem.

It's no problem for me but I'm sure my wife won't like it.
TLGF

[MardyDelica]

this is probably your module your having problem.
if everything works if come out really hot one
same as any normal car. something is sticking in your heater module
cheers;
Mardy

[thelazygreenfox]

Mardy
Something sticking on the air side or the water side of the module?
thx
TLGF

[MardyDelica]

check the module sometime it get stuck you know
thank you

[psilosin]

Reviving an oldie but a goodie since I might tackle this on the weekend. What did you do once you opened the black box to get it all moving again? Clean the contacts? Just gently move the arms back and forth? Voodoo ritual?

I Got Heat!!!!!
The motor that is controlled by the TEMP up and down switch wasn't working, to access it a bunch of lower dash panels and duct work has to come out and then you need very small hands and stubby screwdrivers .
I found the motor was getting power so I took it out and gave it a stern talking to.
Then I took the cover off and there is a multitude of delicate copper arms that rub on contacts on a circuit board.
A little more finger waving mixed with colourful language and I reassembled the casing and hooked it up to 12v power supply and lo and behold it started dancing like a little robot.
So reassembly back into the van with a not unreasonable number of screws left over and I have 60c at the vents where I had 18c 5 hrs ago.
If it crapps out again I'll toss the motor and replace it with a manual cable control.

[Artacoma]

Ha! Be brave
Open the box on a clean flat work surface.
I cleaned the contacts and veeeeerrryyy carefully gave the little copper arms a titch more bend so they put a bit more pressure on the circuit board then redistributed the grease.
The hardest part was getting some slack in the wire harness to get it out.
I was worried the rotation of the plastic gear would be off when I reassembled but it seemed to reset itself once I hooked up power.
The reassembly was waaaaay easy , I guess that explains the extra screws.
This is a finicky fix and you have to be able to remain calm for an extended period ..... be brave ...... it's worth it.

My new van gets compliance inspection monday!!!!!