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Not my week for electrics. Previa was fine yesterday but today I noticed the central locking didn't work, further investigation showed the radio, interior lights and ciggy lighter all don't work. Checked all the fuses and they're ok - relay somewhere perhaps?
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If you are sure that the fuse (and fuse holder) are in good shape then I would be looking for a poor contact somewhere. Have you checked for voltage on the hot side of the relevant fuse?
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I'll dig out my dvm later, only a visual check so far and it's more than one fuse that covers that lot. A word of praise for Toyota while I'm here - the fuse box is in the most sensible place, in the top centre of the dashboard under a lift up panel, no grubbing about upside down under the dash or under the bonnet for me! :)
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Maybe they are all covered by a 'fusible link' under the bonnet. Sounds like that kind of a problem.
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Normd2,
With that many issues I would check the connector that attaches to the bottom of the fuse box, you may find it has moved and is making poor contact
Carse.
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still no joy with the electrics:
lecky moonroof, windows, central locking, heater fan, radio, interior lights, side lights and alarm all don't work
wipers, washers, headlights, instruments all work and car runs fine except three warning lights (oil level, brake, battery) all flicker intermittently (at the same time)
all fuses ok (inc the ones by the battery) and all connections secure. 12.5v engine off and 14.5v engine running. So still head scratching.
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norm
If you'd bothered putting a year and engine; I might be motivated to get the power distribution diagram out.
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if I grovelled a bit and mentioned it's a 1990 2.4 petrol would that help the motivation? please?
{Added to subject header - DD}
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norm
I don't even have a 1990 Previa listed; is this an import Estima? [They are totally different.]
The earliest Previa diagram shows three dash circuit breakers: Main power, locking, front heater. Maybe they've lost feed?
Have you checked all 5 of the fusible links in the engine bay box - #1 looks the most likely.
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it's a genuine UK car not an import - I am very aware of some people calling their 2.2 diesel Estimas and Enimas Previas. There are 5 fuse positions in the engine bay but only 3 are populated, one 20 amp blade fuse and two bigger 30 amp ones.
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norm
That's odd. I've got the fusibles listed [1991-96] as Main 50A; Ign switch 50A; Alternator 100A; ABS 60A; Ign sw 20A.
You'll have to check for feed to those dash-box CBs; second row, two extreme right and one extreme left.
There may be at least one in-line fusible coming off the battery pos - worth a look.
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Yes, it is odd but that's what it has. The previous Previa had a fuse in the 100A position but its casing melted. This car doesn't have one fitted so it may have been modified and situated elsewhere. I'll check the dash CBs tonight.
thanks
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there are three rows of fuses and two readings are strange: one marked 'ST' has 0.8v with the ignition on and another marked 'CHARGE' has 2.4v.
Second row extreme left is marked 'ENGINE' and has 12v, the two extreme right are CIG and EFI and both have 12v. I've no front or rear sidelights or brakelights but the headlights (main and dip) do work and it starts and runs fine.
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norm
Do you have those three circuit breakers in the dash box?
Are you familiar with early Japanese fusible link cables? Were there any visible near the battery pos terminal? I'd expect several.
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The 5 position fuse box is mounted directly on the +ve terminal, all connections seem fine. I swapped all the 'black boxes' from the dash fuse box (I still have the old Previa on SORN) and no joy. I'll charge up the old car's battery and compare readings - I just don't understand this one - why no side/brake lights but headlights do work? Horn works as do hazards and indicators. Why no interior lights or radio but cig lighter socket does work? It was all OK one day but like this the next. And to top it all off I can't find my Haynes manual (even if it is for the American model) to look at the cct diags. There must be a commonality (is that a real word?) for the things that don't work ie a main feed or something.
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norm
It's not failure of the CBs that concerned me; it was loss of feed to them. This has to be a major feed circuit going missing. [Or some sort of very weird earth fault?]
As well as those CBs, it may well feed bus-bars in the dash box that power things like the sidelight relay.
The missing fusibles in that box was my reason for asking about fuse-link wires - those circuits, like the alternator, must be connected to the battery somehow.
Check the full length of the main battery cable right back to the starter bolt and see if there are any tap-offs anywhere.
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well found out about the alternator connection; it's hardwired across the fuse terminals in the battery fusebox. There's a very professional loking heavy duty wire looping underneath the fuse block - if it's not factory fit it's very well done. Still no voltage at the 3 dash c/b's though :( Got to the stage where I went looking for an auto electrician but none to be had in this neck of the woods. Any idea where the sidelight relay is? And any ideas where to look next? Slightly hampered by the loss of the manual with cct diags in it.
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norm
Ahh; there's no feed to the CBs. Now we've got a hard fact to work with.
Drop the fuse box and check the fat red wires coming in. Are they all live and well-connected?
If the alt fusible is hard-wired; are any of the others?
Have any small wires broken off the pos term of the battery and dropped out of sight?
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had to take SWMBO lingerie (I wish) shopping today so no further forward. The 214 managed to drop its exhaust so it was an emergency trip to National so can't afford a sparky now; back to head scratching with the dvm tomorrow.
btw can't see a way to get to the underside of the fusebox - its TDC of the dashboard
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reckon I've found the source of the problem but not the cure yet The wh wire off the 50A fusible by the battery had a s/cct to earth judging by the small area of melted insulation (now taped up). I now have voltage at the 3 c/b's BUT there's 12v on both sides of the 40A one and the leftmost 30A one of the RHS pair. Also if the headlights are turned on they stay on when the switch is returned to the sidelight position. So something's been zapped but can't find what yet (at a guess there's a light relay or controller somewhere which is one of the zappees)
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norm
Oii!! What's this about a 50 amp fusible? You said only two 30s and a 20?
Are you sure that these linking wires under the fusible link box aren't fusible links themselves? They'll look just like a piece of cable except that their insulation is a bit more rubbery.
They can show no outward sign if they're blown.
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fusebox at battery contains two 50A (not 30A as stated previously) fuses (reading the description these are not fusible links simply big fuses ie they fit onto two male blade connectors and have a see-through square cap), one 20A blade fuse and the 100A alternator fuse has been replaced by a heavy wire link looping underneath to a heavy white wire - this is the only link. The 3 fuses here are good.
All fuses in the main fusebox are good.
ccts unaffected are:
electric mirrors, cig lighter, gauges/tacho, starting, charging (14.4v), dip/main headlights, car runs as normal.
The white wire from the 50A fuse (not the heavy white at the 100A position) by the battery appears to have been involved in a s/cct. (not 100% sure this isn't a red herring but there is a small area of exposed wire surrounded by melted insulation now taped up) There is continuity from the battery to the dash c/b's.
ccts affected are:
sidelights, brakelights, interior lights, heater fan, alarm, central locking and electric windows
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could the possible s/cct have done something to the ECU that could result in this or completely unlikely? clutching at straws now... I have a dead Previa of the same vintage available (albeit auto not manual) I could try the ecu from - waste of time?
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norm
I'm still thinking main feed lost. Can you put some load on those CB feeds; a multimeter can be very misleading if there's a poor contact.
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well finally had some time to look into this. Using a sharp probe was able to trace 12v along the white cable and up behind the dashboard. Unfortunatley it then disappears into an area I can't reach and somewhere in there must be a connector that's come adrift. I can take a feed off the A/C fuse (my car doesn't have a/c but the wiring is there) to the 40A C/B and this gives me back most of the circuits I was missing so it's not a dodgy earth or something else holding down the voltage. I really don't fancy dismantling the dash to find this so it may end up going off to the auctions if I can find a decent replacement. I only wish this had happened before I spent some money for its MOT - the joys of motoring! :)
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