Technical HGT 155 electrical woes

[puntodeltathema]

Well, woes is maybe a bit strong. But got you looking.

Hi there - I've been a member here for ages but only post in a blue moon. I'm currently enjoying my sixth Bravo/Brava, which happens to be a 155 HGT - 2000 on an X plate, Steel grey, recently acquired from a more mature owner in Northants (top bloke). A very nice 1 owner car with 75k on the clock.

However - inevitably it has a few electrical maladies. Now, having had 20 Italian cars I know my way round a multimeter but thought I'd just air these in case anybody makes a connection (geddit) and knows of a common problem.

Main issue is the air con. It is fully gassed but although it was working a fortnight ago has now packed up. Gas is still there, but the compressor relay in the infamous front-of-battery box (the first thing I clean up when I get a Bravo/Brava!) doesn't seem to be getting any juice - though the "earth" (that goes back through the injection ECU, pressure switch and dash switch) seems to have 3.5V on it. Hmmm.

Meanwhile - occasionally the idle speed drops which I *think* (unless Italian auto electrical delusion is setting in) is accompanied by a clicking of a relay somewhere behind the glovebox.

Other issues - the door ajar warning light (which I gather is switched by the so-called "ABI" ECU - a bit like an early body computer in Stilo parlance - yep, had those too) has packed up. This seemed to happen about the time the a/c packed up but am probably imagining it. And the ABI is behind the glovebox....

Finally - I don't think this is connected and it's not a big deal but is slightly amusing - when I arm/disarm the alarm, only the indicators on one side of the car light up....

Just in case anyone has any thoughts on all of that....if not, I'll let you know if I solve it.

They are great cars though, aren't they? Seriously, I do like a Bravo/Brava. Despite the erratic Cassino build quality there is so much that is right about them. A sort of Lancia Delta GTie for the 90s....but I'm showing my age now.

Thanks all - random post over!

Nick H
Tonbridge, Kent

 

[varesecrazy]

Hi,
not too sure there.. not enough experience,( despite being on FIAT #27 ..!!)

they certainly sound a bit too coincidental,
apart from the alarm flashers which are "out-there" ; - },
charlie - Oxford

 

[Neverth]

AC relay contact 86 should always have power when ignition is on (as should 30). Injection ECU pulls the other line (contact no 85) to ground when AC ECU commands it, one of those commands goes trough the pressure switch.

The ECU voltage can read anything if you use hi impedance multimeter as when its not engaged it is floating. Put resistor where relay coil wire go and measure voltage across the resistor (you measure if current is going trough it). If current passes trough the resistor when AC is on, but not when it is not, the logic works. Some issue with ECU not being able to ground the current the coil needs to engage.

New groundleads everywhere, chassis-ECU body comes to mind.

Door ajar throws fit but interior lights dont?

 

[puntodeltathema]

Thanks - that's helpful. I'll certainly check the ECU earth and any others I can find. Though I guess that doesn't account for no power at terminal 86. I checked the two 7.5 amp fuses in the owners manual that seemed to relate to the compressor / compressor wiring. Not sure if there are other fuses, though I've been studying the workshop manual wiring diagrams and haven't found any yet.

Yes, oddly the door ajar light is inoperative but all the other ABI functions - interior lights, rear window etc are fine. Unless it's the bulb of course.

Cheers,

Nick

 

[Neverth]

Any power on 30? The coil positive and contact positive should come from same supply. The split is somewhere before the battery relaybox.
page 58 on 4.Wiring diagrams (Marea workshop manual, should apply for 155 hgt too except for wiring colors).

 

[puntodeltathema]

Re: HGT 155 electrical woes (and brake/vacuum issues?)

A slightly belated update/response on this - thanks for the thoughts!

It turns out that the aircon compressor relay and the door ajar warning light are on the same fuse (7.5amp, top right in the fusebox to the right of the steering wheel). Have to confess that on a second look at the fusebox it appears that I blew this fuse whilst playing around with my multimeter - ahem. So that was easily solved. With a new fuse the warning light works again and the relay gets juice.

Working back along the a/c circuit I'm fairly convinced my pressure switch is faulty, as if I bridge the relevant terminals the compressor starts. The pressure switch is certainly leaky. I recall I had a Brava 100 16v where the pressure switch filled up with oil and became inoperative. So I've ordered another switch and my ever-patient a/c specialist is coming back on Friday to fit it. So fingers crossed for the air-con.

The poor idling is still present. Of course it can't be the idle control valve because the 155 doesn't have one. But nothing is showing up - yet - on the diagnostics. Perhaps I'll just have to wait for something to show up.

Another (!) slightly odd issue I thought I might mention is my brakes. After application they tend to bind on slightly for a second or two - but only sometimes. I suspect the servo (it wheezes a bit if you listen hard) though having looked at the workshop manual I don't fancy replacing it (dash and steering column have to come out - nice!). I wonder if some kind of vacuum fault with the servo might be contributing to the poor idle...

Apparently there is a non-return valve in the vacuum line to the servo, but I can't even find the vacuum hose at the moment. Does anyone happen to know where either is?

I do still like it... I do still like it... :bang:

Nick H
Bravo 155 HGT
Tonbridge, Kent

 

[franglais]

Re: HGT 155 electrical woes (and brake/vacuum issues?)

AFAIK, all cars tend to have the one way valve actually attached to the servo, it acts as an intermediary/coupler to the hose and the servo. My marea workshop manual, shows a diagram of what i am completely convinced is the one way valve on the servo, although nowhere can i find a label to give you definite confirmation.
marea workshop manual, vol 1, braking system, page 8

don't worry, once you solve the problems, you fall back in love with the car again, until the next problem crops up that is .....