Quick Summary:
- Look for under-bonnet remote jump posts, often under a red cap.
- Use the correct earth point, not painted metal or fuel lines.
- On start-stop cars, stabilise voltage and connect in the right order.
- Photograph dashboard warnings, jump points, and receipts if it won’t start.
A flat battery is one of those problems that can turn a smooth Texas trip into a stressful delay, especially when you open the bonnet and the battery is not there. Many modern cars, including plenty used for car hire fleets, place the battery in the boot, under a seat, or behind interior trim for packaging and crash safety. To make jump-starting possible, manufacturers often provide remote jump points under the bonnet. Knowing where to look, how to connect safely on start-stop vehicles, and what to document protects you and the vehicle, particularly if the car still will not start.
This guide focuses on practical steps for a Texas hire car, from airport car parks to roadside stops in heat, rain, or dust. If you are collecting a vehicle at major hubs such as Dallas DFW or Houston IAH, it is worth taking two minutes at pickup to locate the jump point diagram in the handbook or on a sticker under the bonnet. That small check can save time later.
Why the battery isn’t under the bonnet on many hire cars
When the battery is relocated, jump-starting becomes less intuitive but not impossible. Common reasons include better weight distribution, freeing space for turbo plumbing or hybrid components, and protecting the battery from engine heat. In many models you will still see a clear positive terminal in the engine bay, with a marked earthing point nearby. Sometimes there is also a dedicated negative post, but more often the negative connection is made to a chassis earth point.
The main risk is not the battery location itself, it is making connections to the wrong metal, reversing polarity, or creating voltage spikes that upset modern electronics. Start-stop systems, battery sensors, and smart charging can be sensitive, so careful setup matters.
Where to look for remote jump points under the bonnet
Start with a systematic search rather than pulling interior panels. Open the bonnet and look for the following:
1) A red “+” jump terminal. This is often inside a small plastic box near the fuse box, or on a stud with a red flip cap. It can be on either side of the engine bay. If you see a thick red cable leading into a fuse box, that is a good sign you are close.
2) A marked earthing point. Manufacturers sometimes provide a metal post, a bracket, or a bolt head with an earth symbol. It may be on the strut tower, a dedicated stud, or a heavy engine lifting eye. This is the preferred point for the negative clamp because it reduces spark risk near any hidden battery venting and gives a reliable connection.
3) The fuse box lid or underside stickers. Some vehicles include diagrams showing jump points. If there is a diagram, take a photo of it so you can refer to it without leaning over the engine bay.
4) Owner’s manual quick-start section. Many car hire cars keep the handbook in the glove box. Look for “jump starting”, “boosting”, or “emergency starting”. If you cannot find the book quickly, a sticker is your next best clue.
If you are at an airport pickup such as San Antonio SAT, ask staff for the vehicle’s jump point location rather than experimenting. That is especially important on hybrids, mild hybrids, and some luxury models where under-bonnet terminals can be covered or unusually placed.
What not to touch when finding an earth point
When you cannot find a clearly marked earth stud, choose a solid unpainted metal part of the engine or chassis. Avoid anything that could be insulated, fragile, or part of another system. Do not connect the negative clamp to:
Painted brackets, which can prevent proper contact and cause arcing.
Thin sheet metal or heat shields, which can bend and create a poor connection.
Fuel lines, brake lines, or air-con pipes, which can be damaged or conduct poorly.
The positive terminal area, which increases the risk of short circuits if the clamp slips.
Good choices are a thick engine lifting eye, a large unpainted bolt on the engine block, or a designated earthing stud. Once clamped, gently wiggle the clamp to confirm it bites into metal and does not slide.
Before you connect anything: quick safety checklist
Texas heat can be intense, and under-bonnet areas can be hotter than you expect. Take basic precautions before connecting jump leads or a booster pack:
Turn everything off: ignition, headlights, cabin fan, heated seats, and phone chargers. Remove keys or keep them well away if the vehicle uses a proximity fob.
Check for obvious damage: leaking fluid, melted wiring, or a cracked battery case if you can see it. If you see anything concerning, stop and contact the rental provider.
Confirm voltage: most hire cars are 12V systems, but some mild hybrids still use a 12V battery plus a separate high-voltage system. Use only the marked 12V jump points.
Use the right equipment: jump leads should be thick enough for the engine size. A quality booster pack is often easier and reduces reliance on another vehicle.
Safe connection order using remote jump points
Use this order to minimise sparks and reduce the chance of reversed polarity. Keep clamps from touching each other and avoid letting them dangle into moving parts.
Step 1: Connect the red clamp to the dead car’s under-bonnet positive jump terminal.
Step 2: Connect the other red clamp to the donor battery positive terminal, or to the booster pack positive.
Step 3: Connect the black clamp to the donor battery negative terminal, or booster pack negative.
Step 4: Connect the remaining black clamp to the dead car’s designated earthing point, away from the positive terminal and away from moving belts.
Then start the donor vehicle and let it run at idle for a couple of minutes, or power on the booster pack, before attempting to start the hire car. If it cranks slowly, wait another few minutes and try again. Avoid repeated long cranks, 5 to 10 seconds per attempt is a sensible maximum to reduce starter and wiring stress.
Start-stop and modern electronics: how to avoid damage
Start-stop vehicles and cars with smart alternators can behave differently after a flat battery. The aim is to avoid sudden voltage spikes and unstable connections.
Prefer a booster pack with surge protection. Many modern packs regulate output better than an improvised jump from another car with thin leads.
Keep loads off during the jump. Do not run heated screens, high fan speed, or infotainment at full volume while starting. Once the engine is running smoothly, you can turn systems back on gradually.
Do not disconnect immediately. Let the engine idle for a minute or two after it starts to stabilise charging. Then remove clamps in reverse order: earth off the hire car first, then donor negative, then donor positive, then hire car positive.
Expect warning lights. After a low voltage event, you may see steering, ABS, traction, or start-stop warnings. Many clear after a short drive. Photograph the warnings before driving, and again after 10 to 15 minutes, so there is a clear record of what changed.
Avoid “revving to charge”. Holding high engine revs can create higher alternator output, but it is not the safest approach on an unfamiliar car. A steady idle is usually enough.
If your Texas car hire is a larger vehicle such as a people carrier, the battery may be higher capacity and take longer to recover. For example, travellers collecting family vehicles via minivan hire in Houston IAH should expect longer charge times after a deep discharge, especially if the vehicle was left with doors open or interior lights on.
If it still won’t start: what to check without causing damage
If the engine does not crank, or clicks once and stops, do not keep trying. Instead, run these checks:
Confirm clamp contact: most failed jumps are poor earth connections or clamps biting on plastic or paint.
Confirm you are on the jump terminal: some fuse boxes have red plastic covers that look like positives but are not the jump post.
Try a different earth point: move the negative clamp to a more solid unpainted bolt or designated stud.
Check the donor source: another car at idle may not supply enough current if its battery is weak. A charged booster pack often works better.
Listen for the fuel pump and dashboard behaviour: if the dash stays dark or resets repeatedly, the 12V system may be extremely low, or there may be a main fuse issue.
If it cranks strongly but will not start, stop. That can indicate immobiliser issues, key recognition problems, or another fault unrelated to the battery. For a car hire vehicle, that is a situation to report rather than troubleshoot extensively.
What photos and notes protect you with a hire car in Texas
Documentation matters because a flat battery can be caused by user error, vehicle condition, or prior usage. Clear, time-stamped evidence helps if there is later confusion about damage or costs.
Take photos of the dashboard: include the mileage, fuel level, warning messages, and the time on your phone screen if possible.
Photograph the jump points you used: one wide shot showing the bonnet open and the clamp placement, plus a close-up of the positive terminal cover or markings.
Note the situation: where the vehicle was parked, approximate temperature, and what happened immediately before it would not start, such as leaving the boot open or using accessory mode.
Keep receipts: if you paid for a booster pack, jump leads, or roadside assistance call-out, keep itemised receipts and take photos of them.
Record who you spoke to: write down the rental company representative name, time, and any advice given. If you are travelling through West Texas and picked up through El Paso ELP, note the location clearly because mobile coverage can vary and time stamps may help establish a timeline.
Also check whether your rental agreement requires you to contact the provider before authorising third-party towing or repairs. The safest approach is to document first, then follow the rental provider’s instructions.
After it starts: how to reduce the chance of another no-start
Once running, drive for at least 20 to 30 minutes where possible to let the battery recover, longer if the battery was deeply discharged. Short stop-start trips can leave the battery undercharged, especially with start-stop disabled or heavy air-conditioning use in Texas heat.
When you park, double-check that lights are off, doors and boot are fully latched, and no USB-powered accessories are left drawing power. If the car is keyless, keep the fob away from the vehicle when parked to reduce the chance of systems staying awake.
If the same car hire vehicle needs a jump again within a day, treat it as a fault rather than bad luck. Document it and report it, because repeated deep discharges can indicate an ageing battery, a charging issue, or a parasitic drain.
FAQ
Q: How do I know if my Texas hire car has remote jump points?
A: Look for a red “+” terminal under the bonnet near the fuse box, and a marked earthing stud nearby. Many vehicles also show jump points on a sticker or in the handbook.
Q: Can I jump-start from the boot battery instead?
A: You can, but it is usually harder and riskier on a hire car because trim panels may need moving. Remote jump points are designed for safe access and are the better option when available.
Q: Will jump-starting damage a start-stop vehicle?
A: Not if done correctly. Keep loads off, connect to the proper earth point, avoid repeated long cranks, and disconnect in reverse order after the engine stabilises.
Q: What if warning lights stay on after the jump-start?
A: Photograph them, then drive briefly to see if they clear as voltage recovers. If critical warnings persist, or the car drives oddly, stop and contact the rental provider.
Q: What evidence should I collect if the hire car won’t start at all?
A: Take photos of the dash, mileage, and warning messages, plus clamp placement if you attempted a jump. Note times, location, and keep any receipts for assistance or equipment.
