The thermo fan switch when it reaches its designed temperature is designed to switch on and when it reaches a lower temperature, it is designed to switch the power off.  The thermo fan switch receives power from the fuse box.  When it reaches a temperature the switch will bridge the terminals thus turning the thermo fan on.

THINGS TO LOOK FOR

Check that the connections are secure and observe that the thermo fan is switching on and off.  Sometimes this may not occur and just manipulating or wiggling the terminals may cause the fan to switch on.  If this is the case then take the terminal off and clean it and refit it.  Otherwise replacing the switch might be another option.

IS IT EXPENSIVE TO REPAIR?

A thermo fan switch is a costly item at around $60.00-$90.00.  It’s better to buy the same type of switch as the original.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT

If stranded the switch may be bypassed and the terminals bridged, but remember this will put a load on the battery and will always turn the fans on when the ignition is turned on.  Or on some vehicles, if you bridge the terminals it may stay on indefinitely.

THINGS TO LOOK FOR
As the thermo fan operates over years the internal mechanisms may start to wear and cause a resistance in the thermo fan relay causing an overload on to the relay and the fuse.  A common sign is a faulty relay.  Melted terminals on the relay indicate that the thermo fan may be overloading the system or drawing too much current caused by an internal fan problem.

IS IT EXPENSIVE TO REPAIR?
If it is a standard thermo relay it may cost around $20.00.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If all other relays are the same specs, ie they may have 30 or 60 amps, make sure that the thermo fan relay is the same as the other and then just swapping the relay with another just to get you home if you’re stranded.

THINGS TO LOOK FOR
It’s always a good idea to look at the thermostatic fan to understand how it operates.  Because thermostatic fans are thermostatically controlled and they should switch on and off.  A good thermostatic fan in a very good cooling system will switch on for somewhere between 20-40 seconds.  If the fan switches on for longer than 60 seconds this might be a cooling system that is unable to cool down with the thermostatic fan.  Another problem might be associated with the cooling system.  If the fan stays on for 5 seconds, this is an excellent cooling system as it never requires a lot of effort from the thermo fan.

THINGS TO LOOK FOR
A starter motor relay if fitted as an after market item may malfunction if the wiring connected to it is not soldered correctly or the relay itself is not of good quality.  Relays are only as good as the power connected to them, the connections and the relay itself must be of good quality.  A clicking starter motor may be the cause of a faulty relay.  Bridging the starter motor may determine this as being a faulty relay, faulty wiring or an intermittent problem with the inhibitor switch.

IS IT EXPENSIVE TO REPAIR?
A standard relay will cost around $25.00.  Consult with your local auto electrician about fitting a relay as he might have the relays made up with the wiring, ready to install onto the starter motor.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If you are stranded on the road and the relay decides to malfunction, bypassing the relay or bridging the starter motor might be the only way to start the engine enabling you to get home.

THINGS TO LOOK FOR
A starter motor may start to create a high pitch when cranking.  This is an indication that the ring gear is wearing out and needs to be attended to ASAP.  Common problems with a starter motor component are breakdowns or a non start.  Starter motors have components that make it reconditionable most of the time.  A click is also another indication that the starter motor is failing to connect inside the internal mechanisms.

IS IT EXPENSIVE TO REPAIR?
Starters motors usually cost between $150.00-$200.00.  A reduction type starter motor may cost from $150.00-$300.00 depending on the repairs.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
Starter motors can be repaired.  Find a very good auto electrician as some will just replace the bare essentials while others will replace it completely.  The option here is if the starter motor can be replaced with a new item for an extra $30.-$50.00 take the replacement option.  As a new unit will come with a guarantee from the manufacturer.  A reconditioned starter motor is only good provided that the auto electrician is reliable.

THINGS TO LOOK FOR
When checking the fuses, it’s best to check the fuses with a test light and don’t rely on the fuse index map indicating where the fuses connect as they may be incorrect.  What is meant by the map is that sometimes when you pull the fuse cover off  you have an index on what the fuses represent eg. wiper blades, wiper motor and you go to check that and it is not the wiper motor fuse.  The wiper motor fuse is in another location.  The most important thing is replacing the fuse with the same amperage.  Also the fuse may look okay but it may not be okay.  The only way to check or test a fuse is with a test light with the ignition on and the engine off.

IS IT EXPENSIVE TO REPAIR?
Replacing a fuse is an easy task if it is a low amperage fuse up to 30 amps but if it is a high amperage fuse it may require a 6, 8 or 10 mm ring spanner to remove it and repair it.  The most important thing to remember is if the fuse breaks when you replace it, it is showing a definite short in the system.  This needs to be attended to ASAP.  Putting a higher amperage fuse in will only load up the wiring and may lead to a more expensive repair as the wiring may melt or be damaged.

This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

THINGS TO LOOK FOR
The computer is located in a cool position away from the foot, usually around the passenger’s floor behind the kick panel or under the passenger seat.  The main cause for a computer breakdown are dry solder joints.  This may cause the engine to cut out, idle rough, non start or have poor fuel economy.  Another cause for computer breakdown is jump starting incorrectly and an open circuit battery.  These are enemies to the computer and need to be avoided at all cost.

IS IT EXPENSIVE TO REPAIR?
The average price of a computer will cost around $500.00 depending on the make.  It is possible to purchase a reconditioned computer from your local spare parts retailer for around $300.00.  When you purchase your computer make sure you receive a receipt and a warranty.  If you buy from the wreckers they may sell the unit without a warranty and it might not operate.

This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

THINGS TO LOOK FOR
Any EFI will suffer if the fuel level runs low.  This being a main focus as this will cause the EFI to fail. Because the fuel operates on pressure and when the fuel level is low there is a possibility of mixing air with the fuel thus creating a power loss. As the fuel system operates on fuel pressure it is easy to see if fuel leaks become apparent.  If the fuel is leaking, turn off the engine ASAP and, at this point, if a rubber hose is split around the injection rail it may be difficult to spot and get.

 
This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

THINGS TO LOOK FOR
When the fuel pump relay seems to be getting warm to hot, this indicates that it is either being overloaded or becoming faulty.  A hot relay is a relay in trouble.  Apart from being hot it may show physical signs of slightly melting around the terminals.  This may be the effect of the cause and the suspect cause being the fuel pump overloading the relay.  If caught early this can prevent a breakdown.

IS IT EXPENSIVE TO REPAIR?
Changing a relay is easy but the cost may range from $8.00-$120.00.  Therefore it is important to check with your auto electrician to make sure it is the relay and not something else causing the relay to malfunction.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If your relay is a common type it may be swapped with an air conditioning relay as they should both be identical, specifically for common type vehicles.  A common type relay may be bypassed as a more complicated type may be bypassed by both but it’s worth trying.  If you want to swap the relays over, make sure that they’re of the same amperage.  You should see 30 amps or 60 amps or 80 amps. They’re both either the same quantity of terminals or voltage or amperage or colour.

 
This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009

THINGS TO LOOK FOR
A breaking fuel pump fuse could be an indication that it is being overload.  This may also happen when running out of fuel.  A fuse breaking more than once a year is a fuse letting you know that it is being overloaded and must be attended to.
IS IT EXPENSIVE TO REPAIR?
the fuel pump fuse costs only 50 cents but the cause may be a short circuit in the wiring of the fuel pump.  This may require the services of a good auto electrician.

TEMPORARY REPAIR AND LONG TERM REPLACEMENT
If  you’re on the road and the fuse has blown it is usually 15 amps.  At your risk you may try 20 amps but this is only a temporary repair as the wiring may overheat costing you more than just a pump.  If the 20 amp fuse blows, protect the wiring and call a tow truck.  It’s a bigger problem than just a temporary repair.

This article is found in the Virtual mechanic CD Rom
You can download it for the price of a latte, but you will learn not to buy a lemon
By Darren Gow-Brown, Melbourne Australia ©2009