Cut out box overheating

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So when I got the car the owner gave me spare (cut out) units, he said they overheat a lot and stop working so he is used to replace them when this happens.

I did a trip yesterday and the AC did indeed stop working and the box was excessively hot. I am not sure if this is normal or maybe the cables have corroded causing too much resistance / heat build up.

The box when covered becomes an oven, so I am not sure how to proceed from here.
I do need to do a proper clean but I have not investigated electrics yet.

Any suggestions ?



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Those are relays.
AC cutoff is based on engine coolant temperature. It will cut off AC to reduce load on the engine when the coolant temperature gets too high.
What year/model/country is your 80?
Which of the 4 relays shown in the relay box are you referring to?
 
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Those are relays.
AC cutoff is based on engine coolant temperature. It will cut off AC to reduce load on the engine when the coolant temperature gets too high.
What year/model/country is your 80?
Which of the 4 relays shown in the relay box are you referring to?

Its a modified 1991 (almost all interior components is 1995 very difficult to say tbh) all relays have the same issue (fuel pump, AC and the other components) the box itself becomes extremally hot with no ventilation when closed.
In other words the whole relay box, it depends on temperature.

Fuel pump, AC and others he faced situations where the car didnt start due to overload from relay. I actually got 4 relays to "swap" when needed with the car
 
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Its a modified 1991 (almost all interior components is 1995 very difficult to say tbh) all relays have the same issue (fuel pump, AC and the other components) the box itself becomes extremally hot with no ventilation when closed.
In other words the whole relay box, it depends on temperature.

Fuel pump, AC and others he faced situations where the car didnt start due to overload from relay. I actually got 4 relays to "swap" when needed with the car
So this is a 3FE engine from a 1991? Or was there an engine swap?
Is it petrol or diesel?
 
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So this is a 3FE engine from a 1991? Or was there an engine swap?
Is it petrol or diesel?
Engine was swapped along with almost everything as well.
Its the petrol 4.5 liter 1HZ.

The car got retrofitted several times hence difficulty finding model, i believe even the frame was also changed. The car number is 1991 but it has 3 ac zones (including arm rest ac) all disk breaks automatic AC and more.
Oil transmission cooling was also added as well as additional tank and extra tire carrier at bottom.
 
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Its the petrol 4.5 liter 1HZ
Did you mean 1FZ-FE? 1HZ is a 4.2L diesel.

You might want to look closely at your VIN and frame numbers:

 
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It was originally a Diesel. I need to get engine number and details but its the 4.5 injection petrol now
 
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The 1FZ-FE typically does not have heat related issues in that relay box because the exhaust manifold is on the opposite side of the engine bay.
As was said earlier, AC cut off is directly related to engine coolant temperature. Do you have an OBD2 port on this truck to monitor actual temps? There should be one on the top of the fuse panel in the cab, assuming that was part of the engine swap.
 
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The 1FZ-FE typically does not have heat related issues in that relay box because the exhaust manifold is on the opposite side of the engine bay.
As was said earlier, AC cut off is directly related to engine coolant temperature. Do you have an OBD2 port on this truck to monitor actual temps? There should be one on the top of the fuse panel in the cab, assuming that was part of the engine swap.
This is a 1992 truck swapped with I'm guessing an OBD1 (93-94) 1FZ-FE.

Doesn't the wiring on that relay box have frequent problems on the 91-92 due to wire/crimp issues on the bottom of the box?

I realize this truck is a Frankenstein, but we have to look at the multiple issues it may have, including a hokey swap and non-USA spec parts originally and probably since.
 
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The 1FZ-FE typically does not have heat related issues in that relay box because the exhaust manifold is on the opposite side of the engine bay.
As was said earlier, AC cut off is directly related to engine coolant temperature. Do you have an OBD2 port on this truck to monitor actual temps? There should be one on the top of the fuse panel in the cab, assuming that was part of the engine swap.
The car has the old OBD one port in the engine bay, I did get a converter and an OBD2 bluethooth device.
Although i was able to detect and connect the software I used (car scanner) was unable to decipher the OBD protocol.

I think something happened in the hot weather, the AC's wouldn't kick in so i swapped the AC relay for fuel pump engine didnt start. Did this with all the spare relay's and the car didn't start only when i placed the original pump relay back did it work.

So I think i might have multiple issues, the relay's need replacement but i suspect something happened in the wiring.
On my boat restoration project one of the main issues I found with the older cables was the wire galvanization meaning I am getting much more resistance in wires causing all sorts of problems.
I had a deeper look at electrics and Its a nightmare.

Just an example !

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So I am going to do the following:
  • Deep engine clean, I cant see anything from all the gunk.
  • Some of the cables appear to be the original ones and I can see the wire due to cover insulation failing!
  • The relays stop working from heat, meaning there is an underlaying problem in electricity (the picture above is a good example as the battery was giving me problems)
  • I need to order some spare relays (i have a friend in UAE and Canada they can bring me a couple of new ones as I cant find them in Egypt new only used and abused)
  • I will need to re-wire the car bit by bit this is just too messy to work with and honestly quite dangerous leaving exposed old cables to touch metal.
Any suggestions / ideas would be great specially if any one did this before on the forums so i can follow.

Dirtiest engine I have ever seen XD
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You show 4 round metal relays in the first picture you posted.
The top right is the EFI MAIN.
The top left is the horn.
The bottom right is unknown.
The bottom left is the condenser fan relay.

The ONLY 2 that are compatible are the EFI MAIN and condenser fan relays. The rest have different pinouts and will not work. This assumes that the relay box is unmolested.
The fuel pump relay does not live in that box. It lives further to the rear of the engine bay almost inside the left fender.

It is possible that the AC won't fire unless the condenser fan fires first, but that is an option we did not get in the US market.
 
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I am finding it tricky to reference manuals to what has been done, the AC is UAE version (hence the 3 Zone part, main, fridge and back)
All 4 are exactly the same specs, pin size and are interchangeable (the one i have any way)

1) EFI = is fuel pump according to previous owner (or thats my assumption)
2) Horn = Horn
3) Bottom right = AC compressor relay
4) Top right = starter motor.

This is all from the owner I will need to probably trace all this to see which is which but for sure the car did not start when i replaced top left one with AC (i.e EFI / fuel pump with AC)

I have no frame of reference so I do apologies on my lack of knowledge
 
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OK, from what's been shown so far, I think it's clear you can't assume anything about your rig matches stock wiring, in the engine bay at least. I would suggest you need to break out the multimeter, and start mapping out your own wiring diagram of your main power circuits. It's really hard to offer advice right now, because almost nothing you've said matches expectations from a stock rig.
 
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OK, from what's been shown so far, I think it's clear you can't assume anything about your rig matches stock wiring, in the engine bay at least. I would suggest you need to break out the multimeter, and start mapping out your own wiring diagram of your main power circuits. It's really hard to offer advice right now, because almost nothing you've said matches expectations from a stock rig.
Ok as I am not sure which year / model the frame is any more, I will take pictures of the fuse box today and try and look at the fuses as well. Maybe the fuse is gone hence why non of the relays are working.
In all cases this is a UAE version so its defiantly going to be different than USA cars (Not to mention the changes that happened over the years)

So I do have multimeter ready but I am not sure how to go about mapping the car's wiring any suggestions ?
 
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Ok as I am not sure which year / model the frame is any more, I will take pictures of the fuse box today and try and look at the fuses as well. Maybe the fuse is gone hence why non of the relays are working.
In all cases this is a UAE version so its defiantly going to be different than USA cars (Not to mention the changes that happened over the years)

So I do have multimeter ready but I am not sure how to go about mapping the car's wiring any suggestions ?
On the RF side of the frame is the VIN of the frame, just behind the RF wheel/axle.
In the cab, the VIN for the body will be both in the left base of the windshield and on a door sticker.

That may be worthwhile to gather both of those pieces of information so they can be cross-referenced.

Also, the head has a number plate attached on the RF side. These are not typically tracked, but you may be able to use it to get close on the year of the engine.
 
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The the chassis is the same, engine & frame have been changed. I will try to find the frame VIN in the base of the windshield, the door sticker has been changed like the one in the engine (same as pic posted previously) by the previous owner(s).
 
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So couldnt find the VIN however I did find out the following:

  1. This is indeed a UAE version, its is very different than USA mostly in cables and fuses.
  2. The fuses are shown below, the only one out of place is the engine starter. For some reason it was placed not in an empty spot (will find out why as the 4 from top is the exact same PIN configuration.
  3. CDS fan is the AC far in front of the radiator, when it doesn't activate the AC wount start.
    Cut out relay box 2.jpeg
The rest is UAE standard (except for a cable loom connecting the 2nd battery to the cut out relay switch and fused for onboard lights etc completely independent from main battery).

And found this on the bonnet which I discovered was yet from an Australian FJ80 ! I did not expect my car to have so much donners from all over the world :D
bonnet.jpeg


So back to the drawing boards !!!!!
 

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