Coolant temp warning, 1.9D

[white exec]

No temp gauge on the 1992 1.9D Millesime, just the usual two temp warning lights, amber and red.

Both lights work (have just relamped the whole instrument panel), but the action of the warning switch on the thermostat housing seems odd.

Warning switch has two connections -
- grounding one connection brings on both lights together
- grounding the other, no lights
- grounding both simultaneously (not sure of the action of the switch), no lights
- disconnecting the switch, both lights on together

Haynes only shows a single warning light, plus two input lines - one via a flasher (deleted by 1989, I think), the other continuous illumination.

Can anyone help with a circuit or workings for the twin lights? Thanks.
_________

Do we have a downloadable source of Citroen workshop volumes for BX - mechanical and electrical wiring diagrams?
Have put in a good bit of work over recent years to help amass pages for XM and Xantia, and would very much value similar for BX, now we have one again.

[rutter123]

Just upgrade your dash clocks with a temp gauge, much more reliable than the "by the way you've just f****d your engine" lamps of (yellow) irreversible damage.and (red) certain death.

[rutter123]

Just upgrade your dash clocks with a temp gauge, much more reliable than the "by the way you've just f****d your engine" lamps of (yellow) irreversible damage.and (red) certain death.

[xantia_v6]

Chris,

You may be able to find fairly complete circuits (and other good info) in l'expert automobile, search for "l'expert automobile 248" or "l'expert automobile citroen BX"

There may be a downloadable copy at: http://ireneuswalter.blogspot.com/2017/ ... n-248.html, but register on that site at your own risk.

[white exec]

Just upgrade your dash clocks with a temp gauge, much more reliable . . .

That was my first preference from the start.
Not having much joy in finding a GTi/etc cluster or gauge section online, so will do a trawl of the huge scrapyards in Malaga.
Finding even Xantias there (for Hydractive valves) was pretty difficult a few years ago, so BX will be a real challenge.

In the meantime, a slim digital temp display module is arriving, which will get discretely mounted in the 17mm space between instrument pod and column shroud.

Intention is also to add a header tank to the system. Inherited HG failure on our previous 19RD. It went went through one further HG before I replaced the head with new as well. Then added a header tank, and no more problems, even with copious towing.

[white exec]

Mike, thanks. Will try both of those.

[white exec]

Mike,
Have downloaded the RTA BX diesel pdf volume, direct from RTA (€32). Looked a safe bet.
Thanks again for the pointer.
C.

[rutter123]

I butchered the insides of a 50mm round digital temp gauge and managed to fit it into the bottom right side of the instrument cluster, utilising a Fiat temp sender M12x1. 25 in place of the yellow lamp warning sender on the start housing, seems effective enough running at 70-80 degrees

[white exec]

I might have to do something similar, maybe re-purposing a BX fuel gauge (which are more easy to find).
All the gauges are just voltmeters - except the speedo, alas! - so possible to get creative around a suitable temp sensor.
Main problems are linearity, and physical appearance - not least the need for a backlit scale/figures.
___________

On a less challenging front, did the suggested mod to the instrument illumination, and inserted a small relay in the rheostat line, so that the instruments are only lit when both IGN and Lights are on.

Not yet seen any really acceptable LED substitution for the 1.2W tungstens. Their filaments throw most of their light out sideways (which avoids hot-spots and glare), and the very warm colour balance is well matched for the green and orange.

Pulling the instrument pod out is a bit of a pain (the first time, anyway*), but unless you insist on running the tungstens full-time, and at max brightness, lamp life is going to be long. 14v bulbs (which some electronics suppliers stock) will help. On the brightness setting, worth remembering that a 10% reduction in supply voltage for a tungsten lamp results in 400% lamp life . . . so well worth avoiding anything close to maximum brightness.

* Everything eases with practice
* Small hands and slim wrists an advantage (for the two wingnuts)
* Unhitch upper speedo cable from the lower half (below the battery) to allow inst.pod to pull out further
* Realise how the speedo cable 'unclip' widget actually works

[rutter123]

I have several t/d clusters with fuel gauge intact if u need, may even have a temp gauge in one of them

[white exec]

If you can find a temp gauge panel piece, that would be splendid!

[David]

It's worth baring in mind that some of the instrument panels out of the Peugeot 205 and 309 (I think) will fit the BX. The colours and fonts are different though, but if that didn't bother you then you could make one panel out of two, perhaps changing the gauges at the sides so they'd be orange, and leaving the centre alone, do they'd still be green.

Also, if you're removing a temp switch, I'd remove the one that controls the red light and plug its plug onto the yellow switch, that way if it overheats, then the light will come on sooner and you might have a chance before it destroys the engine. (It was suggested by Matt elsewhere on the forum, but it's a good idea, and I've done it myself).

I did the mod with a relay to make the lights only come on with the headlights and ignition too; it's worthwhile & stops the lights being on constantly and unnecessarily burning out the bulbs prematurely, which to me seems daft.

Hope that helps.

[white exec]

Useful tips, thanks David.
I'll only add the pukka temp gauge(s) to the dash, for appearance sake, so will keep looking.
As a temporary measure, will be fitting a digital display in the gap between steering column shroud and pod ledge.

With our original '89 19RD atmo, after two failed HGs, we replaced the head with a brand new bare one (and transferred cam, valves, etc), and added a header tank and a second fan, as the car would then be used for lots of caravan towing.

A temp gauge was never added, but we retained the two-stage (amber, red) temp warning, and used the spare turbo/cat lights to show when the fans were operating - amber for slow speed, red for fast. Also equipped the recessed switch panel with a rotary switch that allowed the fans to be turned on manually - slow, fast, or immediate-fast-by-thermoswitch.

The advantage of the header tank (an Austin-Rover vertical one, fitted high up on the firewall above the gearbox, and piped into the thermostat housing via an unused snout) was that the radiator was always kept completely full, instead of the designed-in void at the top.

The car did over 130k mi beyond all that, and reliably towed all over Europe, including Alps, Picos de Europa, and 45°central Spain. She was finally retired at the end of 1998, when we bought the 2.5 XM. Very much missed, hence her replacement now!