Peugoet temp sensor and BITRON unit problem.

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indigo200
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Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

Wired it up however not given it a run yet however I'm getting no ristiance difference between both the look and fresh cable. Maybe it will be better when it's hot, maybe I should order some more Brown sensors by different manufactures and compair them! I'm out of ideas.
indigo200
Posts: 13
Joined: 05 Sep 2016, 19:47
Location: milton kynes
My Cars: Peugoet 405 saloon 1995 (XU7)
Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

Anyone have any ideas? I really don't want to scrap it. If I do does anyone know if anyone wants a set of MI16 alloys and interior!
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white exec
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and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
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Re: Peugoet temp sensor and BITRON unit problem.

Post by white exec »

Hi Indigo,

I have gone though your complete thread. It's very detailed and methodical - well done there.

JFI, resistive temp sensors normally are "straight line" in their response, but the electronics they are connected to may not be linear.

You've established that the brown sensor is PTC, and hung some values on it for several temperatures.
Unlikely that your new sensor is faulty, as it produces the same result as the original, so no need to buy any more.
Unplugging the brown sensor (infinite resistance) brings on the fans full speed - This is correct.
Your test with a substituted test potentiometer also shows, as you say, correct operation of the fans:
- low resistance = shorted = failed sensor = fast speed
- 2k8-3k0 = half speed (equiv to water temp below 100C)
- 3k0-ish+ = full speed (equiv to water temp above 100C or more).
So all that is looking good.
Bitron appears to be doing its stuff.

You are right in that the next step, logically, is to wire the brown sensor direct to the Bitron box with two new cables.
Resistance of cabling between box and sensor should obviously be zero.
Will be interesting to see the result.
Might not be a dodgy OE cable; could be a dodgy connector.

There's also the issue of whether the engine is actually reaching the water temperatures specified to bring on Lo speed and then Hi.
Switching on the AC works (brings on fans at half speed).
You might need to use a decent thermometer to check what sort of water temp there actually is at the sensor location.
Some engines do run somewhat chilly, or can have thermostats missing or stuck open.

Watching the space!

PS It is also possible to check out the 3-relay-and-2-fans end of the business, by unplugging the bitron box, and simply driving the relays/fans with appropriate +12 and GND connections.
Your wiring diagram above (assuming that's exactly the right one) shows the 3 relays connected together to achieve
(a) fans in series (= slow speed)
(b) fans in parallel (= high speed).

There are just two activating connections (both GND connections) that do this, marked 1st velocidad and 2nd velocidad on the diagram. ***

ALL the other GND and +12 supplies to the relays must be present to make these work.
GND'ing these two (one at a time!) should bring on slow and high speed.

My reading of this, however, is that all of the relay-fan side of things is in order.

*** On older cars (eg BX), this same 3-relay-2-fan arrangements was simply operated directly by a two-stage "thermoswitch", screwed into the radiator side tank. The switch closed first one pair of contacts, and then a second set as the temperature went higher.
Chris
indigo200
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Joined: 05 Sep 2016, 19:47
Location: milton kynes
My Cars: Peugoet 405 saloon 1995 (XU7)
Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

Thanks for the update! I'm going to have a go wiring it up like a sensor like the old style cars like you said!
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Re: Peugoet temp sensor and BITRON unit problem.

Post by xantia_v6 »

You still haven't told us how hot the engine gets.
indigo200
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Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

I'm not sure what you mean Xantia v6, It reacts like any other engine that has no cooling.

The engine just gets hotter and hotter, I turn it off before it goes over 100c as I dont want to damage anything but it goes over 110c and I imagine it would not stop there.

The blanker bung for the radiator uses a 12mm hex key so I have had to order up a new hex key. will need to wait till that comes.
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white exec
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Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Peugoet temp sensor and BITRON unit problem.

Post by white exec »

Would be good to know exactly how hot the water gets (at the temp sensor position), using a proper thermometer. The dash gauge is driven by its own temp sensor (there are usually three) and these gauges are not particularly accurate. Quite possible that gauge says things are 100+, even though they are not. If this is so, it is possible that the engine is not actually getting hot enough to bring on the fans. Just possible; needs confirming.

Have you managed to do any direct connection of the new sensor direct to your Bitron with new cable yet?
When you do, try it with a spare (good) sensor sitting in boiling/heated water, and see if/when this will bring on the fans.
Chris
indigo200
Posts: 13
Joined: 05 Sep 2016, 19:47
Location: milton kynes
My Cars: Peugoet 405 saloon 1995 (XU7)
Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

I put the bitron sensor in boiling water and tried it in the systems and it seems to behave differently. I'm not bothering with the Aircon moduel any more now. I have put a two stage switch into my radiator like on a older one. I just need to bleed the system now.

Does anyone know a good way to bleed these cars? There is two bleed points (one on the rad and the other on the thermostat housing). I open them both and get fluid however I always get a airlock. It's not after hours of messing around and squeezing the right pipes then rebleeding the system do I get rid of the airlock! Seems to be on the upper rad hose.

I am more interested in getting it going as I just gave my 106 away after it failed on so many things during inspection! =) hopefully I can get this 405 going!
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white exec
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Posts: 7445
Joined: 21 Dec 2015, 12:46
Location: Sayalonga, Malaga, Spain
My Cars: 1996 XM 2.5TD Exclusive hatch RHD
1992 BX19D Millesime hatch LHD
previously 1989 BX19RD, 1998 ZX 1.9D auto, 2001 Xantia 1.8i auto
and lots of Rovers before that: 1935 Ten, 1947 Sixteen, 1960 P5 3-litre, 1966 P6 2000, 1972 P6 2000TC, and 1975 P6B 3500S
x 1752

Re: Peugoet temp sensor and BITRON unit problem.

Post by white exec »

I didn't realise you were going to go down the (older) thermoswitch route, but no matter, if it works and brings on the fans first at slow speed, and then at fast, that's good enough.

Herebelow a circuit which shows just that sort of set-up. I did this myself on a BX19RD, when converting from one fan to two:

Image

The circuit uses exactly the same triple-relay set-up found on our cars, but is fed by thermoswitch (and not ECU, where the arrangement is exactly the same). It's also essentially the same as the Italian circuit you posted above.

It's also possible to have the AC automatically switch the fans on to Lo speed. The circuit above shows this, too, as an option.

There is also the option of a dash-mounted manual control switch, and indicators, at the bottom of the circuit. This can be omitted.

Bleeding
Haynes is pretty good at detailing how to do this. I don't have a Haynes 405 manual, but maybe you do.
For other Cit/Peu models, there are often several bleed screws:
- radiator top
- radiator top hose
- thermostat housing
- heater-feed pipe at back of engine, next to the firewall/bulkhead
- and maybe others.

Preferred method is to install a "header" bottle (1-litre will do) into the top of the expansion tank, something like this:

Image

Bottle (with base removed) is wedged into the filler neck, in such a way that it blocks off the drain hole at the side of the filler neck. I used a short length of old radiator hose to do this.
Run engine until hot, keeping the header bottle at least half full, and until the fans cut in (says the manual, usually), and keep it running*.
This might take 20 mins+ on a diesel.
Keeping the header bottle at least half full, open each of the bleed screws in turn to bleed off air.
The header bottle provides extra "head" (system pressure), enough to displace trapped air.
Squeezing the radiator top hose will also encourage air to bubble out of the system, and up into the header bottle.
When done, engine off, and allow to cool.
Remove bottle, and check coolant level when cold.

* If bottle vibration/splashing is a problem, attach a weight to the bottle's top edge, which will quieten things down.
Chris
indigo200
Posts: 13
Joined: 05 Sep 2016, 19:47
Location: milton kynes
My Cars: Peugoet 405 saloon 1995 (XU7)
Peugoet 106 3 door 2002 (TU1)

Re: Peugoet temp sensor and BITRON unit problem.

Post by indigo200 »

Wow thanks for all that, A lot a great data there! Will try to find some time to get it all going! thanks very much!
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